Prepare for and practice interview questions from System One.

System One Interview Questions

System One Interview Guides

Machine Learning

How would you encode a categorical variable with thousands of distinct values

Encoding Categorical Features

Which model would perform better and why?

Booking Regression

How do we deal with the missing square footage data to construct our model

Missing Housing Data

How would we build a model to detect fraud and text customers to approve or deny fraudulent transactions

Bank Fraud Model

How would we know if we have enough data to create an accurate enough model?

One Million Rides

Data Structures & Algorithms

Given two sorted lists, write a function to merge them into one sorted list.

Merge Sorted Lists

Find the missing integer from a array of consequtive integers

Find the Missing Number

Write a function n_frequent_words that returns the top N frequent words and their frequencies, and state its run-time

Get Top N Frequent Words

Write a function to return the names and resume IDs for resumes whose IDs have not already been scraped

New Resumes

Given an integer N, write a function that returns all of the prime numbers up to N

Prime to N

Write a query to select the top 3 departments with at least ten employees and rank them according to the percentage of their employees making over 100K in salary.

Employee Salaries

Select the 2nd highest salary in the engineering department

2nd Highest Salary

Calculate the first touch attribution for each `user_id` that converted.

First Touch Attribution

Write a query to return the two students with the closest test scores and the score difference

Closest SAT Scores

Write a query to get the total three-day rolling average for deposits by day

Rolling Bank Transactions

Probability

First to Six

What is the probability that each subsequent card is larger than the previous drawn card when picking three cards from a shuffled deck of 500 cards

500 Cards

What is the probability that it's actually raining in Seattle?

Raining in Seattle

What is the probability that item X would be found on Amazon's website?

Found Item

Given three uniform(0,4) random variables, what is the probability that the median of them is greater than 3?

Median Probability

Data Modeling

Design a data warehouse for a new online retailer

Retailer Data Warehouse

Design a database schema for a Tinder-style dating app and discuss needed optimizations

Swiping App Design

System design for a digital classroom service.

Digital Classroom System Design

Use of foreign key constraints instead of BIGINTS

Foreign Key Constraints

Design a database for a stand-alone fast food restaurant

Fast Food Database

<p>Write a SQL query to select the 2nd highest salary in the engineering department.</p>

<p><strong>Note:</strong> If more than one person shares the highest salary, the query should select the next highest salary.</p>

<p><strong>Example:</strong></p>

<p><strong>Input:</strong></p>

<p><code>employees</code> table</p>

<table>
<thead>
<tr>
<th>Column</th>
<th>Type</th>
</tr>
</thead>

<tbody>
<tr>
<td><code>id</code></td>
<td>INTEGER</td>
</tr>

<tr>
<td><code>first_name</code></td>
<td>VARCHAR</td>
</tr>

<tr>
<td><code>last_name</code></td>
<td>VARCHAR</td>
</tr>

<tr>
<td><code>salary</code></td>
<td>INTEGER</td>
</tr>

<tr>
<td><code>department_id</code></td>
<td>INTEGER</td>
</tr>
</tbody>
</table>
<p><code>departments</code> table</p>

<table>
<thead>
<tr>
<th>Column</th>
<th>Type</th>
</tr>
</thead>

<tbody>
<tr>
<td><code>id</code></td>
<td>INTEGER</td>
</tr>

<tr>
<td><code>name</code></td>
<td>VARCHAR</td>
</tr>
</tbody>
</table>
<p><strong>Output:</strong></p>

<table>
<thead>
<tr>
<th>Column</th>
<th>Type</th>
</tr>
</thead>

<tbody>
<tr>
<td><code>salary</code></td>
<td>INTEGER</td>
</tr>
</tbody>
</table>


<p>Given the <code>employees</code> and <code>departments</code> table, write a query to get the top 3 highest employee salaries by department. If the department contains less that 3 employees, the top 2 or the top 1 highest salaries should be listed (assume that each department has at least 1 employee). </p>

<p><em>Note: The output should include the full name of the employee in one column, the department name, and the salary. The output should be sorted by department name in ascending order and salary in descending order.</em> </p>

<p><strong>Example:</strong></p>

<p><strong>Input:</strong></p>

<p><code>employees</code> table</p>

<table>
<thead>
<tr>
<th>Column</th>
<th>Type</th>
</tr>
</thead>

<tbody>
<tr>
<td><code>id</code></td>
<td>INTEGER</td>
</tr>

<tr>
<td><code>first_name</code></td>
<td>VARCHAR</td>
</tr>

<tr>
<td><code>last_name</code></td>
<td>VARCHAR</td>
</tr>

<tr>
<td><code>salary</code></td>
<td>INTEGER</td>
</tr>

<tr>
<td><code>department_id</code></td>
<td>INTEGER</td>
</tr>
</tbody>
</table>
<p><code>departments</code> table</p>

<table>
<thead>
<tr>
<th>Column</th>
<th>Type</th>
</tr>
</thead>

<tbody>
<tr>
<td><code>id</code></td>
<td>INTEGER</td>
</tr>

<tr>
<td><code>name</code></td>
<td>VARCHAR</td>
</tr>
</tbody>
</table>
<p><strong>Output</strong>:</p>

<table>
<thead>
<tr>
<th>Column</th>
<th>Type</th>
</tr>
</thead>

<tbody>
<tr>
<td><code>employee_nam</code>e</td>
<td>VARCHAR</td>
</tr>

<tr>
<td><code>department_name</code></td>
<td>VARCHAR</td>
</tr>

<tr>
<td><code>salary</code></td>
<td>INTEGER</td>
</tr>
</tbody>
</table>


Get the top 3 highest employee salaries by department

Top Three Salaries

<p>We’re given a table of bank transactions with three columns, <code>user_id</code>, a deposit or withdrawal value (determined if the value is positive or negative), and <code>created_at</code> time for each transaction.</p>

<p>Write a query to get the total three-day rolling average for deposits by day.</p>

<p><em>Note: Please use the format <code>&#39;%Y-%m-%d&#39;</code> for the date in the outout</em></p>

<p><strong>Example:</strong></p>

<p><strong>Input:</strong></p>

<p><code>bank_transactions</code> table</p>

<table>
<thead>
<tr>
<th>Column</th>
<th>Type</th>
</tr>
</thead>

<tbody>
<tr>
<td><code>user_id</code></td>
<td>INTEGER</td>
</tr>

<tr>
<td><code>created_at</code></td>
<td>DATETIME</td>
</tr>

<tr>
<td><code>transaction_value</code></td>
<td>FLOAT</td>
</tr>
</tbody>
</table>
<p><strong>Output:</strong></p>

<table>
<thead>
<tr>
<th>Column</th>
<th>Type</th>
</tr>
</thead>

<tbody>
<tr>
<td><code>dt</code></td>
<td>VARCHAR</td>
</tr>

<tr>
<td><code>rolling_three_day</code></td>
<td>FLOAT</td>
</tr>
</tbody>
</table>


<p>Given a table of students and their SAT test scores, write a query to return the two students with the closest test scores with the score difference.</p>

<p>If there are multiple students with the same minimum score difference, select the student name combination that is higher in the alphabet. </p>

<p><strong>Example:</strong></p>

<p><strong>Input:</strong></p>

<p><code>scores</code> table</p>

<table>
<thead>
<tr>
<th>Column</th>
<th>Type</th>
</tr>
</thead>

<tbody>
<tr>
<td><code>id</code></td>
<td>INTEGER</td>
</tr>

<tr>
<td><code>student</code></td>
<td>VARCHAR</td>
</tr>

<tr>
<td><code>score</code></td>
<td>INTEGER</td>
</tr>
</tbody>
</table>
<p><strong>Output:</strong></p>

<table>
<thead>
<tr>
<th>Column</th>
<th>Type</th>
</tr>
</thead>

<tbody>
<tr>
<td><code>one_student</code></td>
<td>VARCHAR</td>
</tr>

<tr>
<td><code>other_student</code></td>
<td>VARCHAR</td>
</tr>

<tr>
<td><code>score_diff</code></td>
<td>INTEGER</td>
</tr>
</tbody>
</table>


<p>Given two sorted lists, write a function to merge them into one sorted list.</p>

<p><em>Bonus: What’s the time complexity?</em></p>

<p><strong>Example:</strong></p>

<p><strong>Input:</strong></p>

<pre tabindex="0" class="chroma"><code><span class="line"><span class="cl"><span class="n">list1</span> <span class="o">=</span> <span class="p">[</span><span class="mi">1</span><span class="p">,</span><span class="mi">2</span><span class="p">,</span><span class="mi">5</span><span class="p">]</span>
</span></span><span class="line"><span class="cl"><span class="n">list2</span> <span class="o">=</span> <span class="p">[</span><span class="mi">2</span><span class="p">,</span><span class="mi">4</span><span class="p">,</span><span class="mi">6</span><span class="p">]</span>
</span></span></code></pre>

<p><strong>Output:</strong></p>

<pre tabindex="0" class="chroma"><code><span class="line"><span class="cl"><span class="k">def</span> <span class="nf">merge_list</span><span class="p">(</span><span class="n">list1</span><span class="p">,</span><span class="n">list2</span><span class="p">)</span> <span class="o">-&gt;</span> <span class="p">[</span><span class="mi">1</span><span class="p">,</span><span class="mi">2</span><span class="p">,</span><span class="mi">2</span><span class="p">,</span><span class="mi">4</span><span class="p">,</span><span class="mi">5</span><span class="p">,</span><span class="mi">6</span><span class="p">]</span>
</span></span></code></pre>


<p>You have two sorted lists, one with m elements and one with n elements. What would be the time complexity of merging the two lists via merge sort?</p>


You have two sorted lists, one with m elements and one with n elements. What would be the time complexity of merging the two lists via merge sort? 

Merging Lists Complexity

<p>Given a <code>employees</code> and <code>departments</code> table, select the top 3 departments with at least ten employees and rank them according to the percentage of their employees making over 100K in salary.</p>

<p><strong>Example:</strong></p>

<p><strong>Input:</strong></p>

<p><code>employees</code> table</p>

<table>
<thead>
<tr>
<th>Columns</th>
<th>Type</th>
</tr>
</thead>

<tbody>
<tr>
<td><code>id</code></td>
<td>INTEGER</td>
</tr>

<tr>
<td><code>first_name</code></td>
<td>VARCHAR</td>
</tr>

<tr>
<td><code>last_name</code></td>
<td>VARCHAR</td>
</tr>

<tr>
<td><code>salary</code></td>
<td>INTEGER</td>
</tr>

<tr>
<td><code>department_id</code></td>
<td>INTEGER</td>
</tr>
</tbody>
</table>
<p><code>departments</code> table</p>

<table>
<thead>
<tr>
<th>Columns</th>
<th>Type</th>
</tr>
</thead>

<tbody>
<tr>
<td><code>id</code></td>
<td>INTEGER</td>
</tr>

<tr>
<td><code>name</code></td>
<td>VARCHAR</td>
</tr>
</tbody>
</table>
<p><strong>Output:</strong></p>

<table>
<thead>
<tr>
<th>Column</th>
<th>Type</th>
</tr>
</thead>

<tbody>
<tr>
<td><code>percentage_over_100k</code></td>
<td>FLOAT</td>
</tr>

<tr>
<td><code>department_name</code></td>
<td>VARCHAR</td>
</tr>

<tr>
<td><code>number_of_employees</code></td>
<td>INTEGER</td>
</tr>
</tbody>
</table>


<p>Given a table called <code>employees</code>, get the largest salary of any employee by department</p>

<p><strong>Example:</strong></p>

<p><strong>Input:</strong></p>

<p><code>employees</code> table</p>

<table>
<thead>
<tr>
<th>Column</th>
<th>Type</th>
</tr>
</thead>

<tbody>
<tr>
<td><code>id</code></td>
<td>INTEGER</td>
</tr>

<tr>
<td><code>department</code></td>
<td>VARCHAR</td>
</tr>

<tr>
<td><code>salary</code></td>
<td>INTEGER</td>
</tr>
</tbody>
</table>
<p><strong>Output:</strong></p>

<table>
<thead>
<tr>
<th>Column</th>
<th>Type</th>
</tr>
</thead>

<tbody>
<tr>
<td><code>department</code></td>
<td>VARCHAR</td>
</tr>

<tr>
<td><code>largest_salary</code></td>
<td>INTEGER</td>
</tr>
</tbody>
</table>


Write a query to get the largest salary of any employee by department

Largest Salary by Department

<p>Let’s say that your company is running a standard control and variant AB test on a feature to increase conversion rates on the landing page. The PM checks the results and finds a .04 p-value.</p>

<p>How would you assess the validity of the result?</p>


How would you assess the validity of the result?

Experiment Validity

A/B Testing

<p>The schema below is for a retail online shopping company consisting of two tables, <code>attribution</code> and <code>user_sessions</code>.</p>

<ul>
<li><p>The attribution table logs a session visit for each row.</p></li>

<li><p>If <code>conversion</code> is <code>true</code>, then the user converted to buying on that session.</p></li>

<li><p>The <code>channel</code> column represents which advertising platform the user was attributed to for that specific session.</p></li>

<li><p>Lastly the <code>user_sessions</code> table maps many to one session visits back to one user.</p></li>
</ul>

<p>First touch attribution is defined as the channel with which the converted user was associated when they first discovered the website.</p>

<p>Calculate the first touch attribution for each <code>user_id</code> that converted. </p>

<p><strong>Example:</strong></p>

<p><strong>Input:</strong></p>

<p><code>attribution</code> table</p>

<table>
<thead>
<tr>
<th>Column</th>
<th>Type</th>
</tr>
</thead>

<tbody>
<tr>
<td><code>session_id</code></td>
<td>INTEGER</td>
</tr>

<tr>
<td><code>channel</code></td>
<td>VARCHAR</td>
</tr>

<tr>
<td><code>conversion</code></td>
<td>BOOLEAN</td>
</tr>
</tbody>
</table>
<p><code>user_sessions</code> table</p>

<table>
<thead>
<tr>
<th>column</th>
<th>type</th>
</tr>
</thead>

<tbody>
<tr>
<td><code>session_id</code></td>
<td>INTEGER</td>
</tr>

<tr>
<td><code>created_at</code></td>
<td>DATETIME</td>
</tr>

<tr>
<td><code>user_id</code></td>
<td>INTEGER</td>
</tr>
</tbody>
</table>
<p><strong>Example output:</strong></p>

<table>
<thead>
<tr>
<th><code>user_id</code></th>
<th><code>channel</code></th>
</tr>
</thead>

<tbody>
<tr>
<td>123</td>
<td>facebook</td>
</tr>

<tr>
<td>145</td>
<td>google</td>
</tr>

<tr>
<td>153</td>
<td>facebook</td>
</tr>

<tr>
<td>172</td>
<td>organic</td>
</tr>

<tr>
<td>173</td>
<td>email</td>
</tr>
</tbody>
</table>


<p>Given an integer <code>N</code>, write a function that returns a list of all of the prime numbers up to <code>N</code>.</p>

<p><em>Note: Return an empty list there are no prime numbers less than or equal to <code>N</code>.</em></p>

<p><strong>Example:</strong></p>

<p><strong>Input:</strong></p>

<pre tabindex="0" class="chroma"><code><span class="line"><span class="cl"><span class="n">N</span> <span class="o">=</span> <span class="mi">3</span>
</span></span></code></pre>

<p><strong>Output:</strong></p>

<pre tabindex="0" class="chroma"><code><span class="line"><span class="cl"><span class="k">def</span> <span class="nf">prime_numbers</span><span class="p">(</span><span class="n">N</span><span class="p">)</span> <span class="o">-&gt;</span> <span class="p">[</span><span class="mi">2</span><span class="p">,</span><span class="mi">3</span><span class="p">]</span>
</span></span></code></pre>


<p>Let’s say you work at a file-hosting website. You have information on user’s daily downloads in the <code>download_facts</code> table</p>

<p>Use the window function <code>RANK</code> to display the top three users by downloads each day. Order your data by <code>date</code>, and then by <code>daily_rank</code></p>

<p><strong>Example:</strong></p>

<p><strong>Input:</strong></p>

<p><code>download_facts</code> table</p>

<table>
<thead>
<tr>
<th>Column</th>
<th>Type</th>
</tr>
</thead>

<tbody>
<tr>
<td><code>user_id</code></td>
<td>INTEGER</td>
</tr>

<tr>
<td><code>date</code></td>
<td>DATE</td>
</tr>

<tr>
<td><code>downloads</code></td>
<td>INTEGER</td>
</tr>
</tbody>
</table>
<p><strong>Output:</strong></p>

<table>
<thead>
<tr>
<th>Column</th>
<th>Type</th>
</tr>
</thead>

<tbody>
<tr>
<td><code>daily_rank</code></td>
<td>INTEGER</td>
</tr>

<tr>
<td><code>user_id</code></td>
<td>INTEGER</td>
</tr>

<tr>
<td><code>date</code></td>
<td>DATE</td>
</tr>

<tr>
<td><code>downloads</code></td>
<td>INTEGER</td>
</tr>
</tbody>
</table>


Write a query to display the top three users by downloads each day

Top 3 Users

<p>Amy and Brad take turns in rolling a fair six-sided die. Whoever rolls a “6” first wins the game. Amy starts by rolling first.</p>

<p>What’s the probability that Amy wins?</p>


Amy and Brad take turns in rolling a fair six-sided die. Whoever rolls a “6” first wins the game. Amy starts by rolling first.

What’s the probability that Amy wins?

<p>Let’s say we’re comparing two machine learning algorithms. In which case would you use a bagging algorithm versus a boosting algorithm? </p>

<p>Give an example of the tradeoffs between the two.</p>


<p>In machine learning, when would you use a bagging algorithm over a boosting algorithm?</p>


In machine learning, when would you use a bagging algorithm over a boosting algorithm?

Bagging vs. Boosting

In which case would you use a bagging algorithm versus a boosting algorithm

Bagging vs Boosting

<p>Let’s say you’re working in HR at a major tech company, and they ask you to find employees with a high probability of leaving the company. They tell you these employees perform well but have the lowest pay.</p>

<p>Given two tables, <code>employees</code>  and <code>projects</code>, find the five lowest-paid employees who have completed at least three projects.</p>

<p>Note: We consider projects to be completed when they have an end date, which is the same as saying their <code>End_dt</code> is not <code>NULL</code>.</p>

<p><strong>Example:</strong></p>

<p><strong>Input:</strong></p>

<p><code>employees</code> table</p>

<table>
<thead>
<tr>
<th>id</th>
<th>salary</th>
</tr>
</thead>

<tbody>
<tr>
<td>INTEGER</td>
<td>FLOAT</td>
</tr>
</tbody>
</table>
<p><code>projects</code> table</p>

<table>
<thead>
<tr>
<th>employee_id</th>
<th>project_id</th>
<th>Start_dt</th>
<th>End_dt</th>
</tr>
</thead>

<tbody>
<tr>
<td>INTEGER</td>
<td>INTEGER</td>
<td>DATETIME</td>
<td>DATETIME</td>
</tr>
</tbody>
</table>
<p><strong>Output:</strong></p>

<table>
<thead>
<tr>
<th>employee_id</th>
</tr>
</thead>

<tbody>
<tr>
<td>INTEGER</td>
</tr>
</tbody>
</table>


Find the five employees with the hightest probability of leaving the company

Top 5 Turnover Risk

<p>You are about to get on a plane to Seattle. You want to know if you should bring an umbrella. You call 3 random friends of yours who live there and ask each independently if it’s raining. Each of your friends has a <sup>2</sup>⁄<sub>3</sub> chance of telling you the truth and a <sup>1</sup>⁄<sub>3</sub> chance of messing with you by lying. All 3 friends tell you that “Yes” it is raining.</p>

<p>What is the probability that it’s actually raining in Seattle?</p>


<p>What is the <strong>main</strong> difference between the Frequentist and Bayesian methods of probabilistic analysis?</p>


What is the **main** difference between the Frequentist and Bayesian methods of probabilistic analysis?

Frequentist Vs Bayesian Analysis

<p>Let’s say you run a wine house. You have detailed information about the chemical composition of wines in a <code>wines</code> table.</p>

<p>One day, a customer comes asking specifically for a wine that has</p>

<ul>
<li>Greater or equal to than 13% alcohol content</li>
<li>Ash content less than 2.4</li>
<li>A color intensity less than 3</li>
</ul>

<p>Write a query to find the <code>id</code>s of suitable wines for this customer.</p>

<p><em>Note:</em> All percentages are reported with two numbers before the decimal point; for example, 13.55% is represented as <code>13.55</code> instead of <code>0.1355</code>.</p>

<p><strong>Example:</strong></p>

<p><strong>Input:</strong></p>

<p><code>wines</code> table</p>

<table>
<thead>
<tr>
<th>Column</th>
<th>Type</th>
</tr>
</thead>

<tbody>
<tr>
<td><code>id</code></td>
<td>INTEGER</td>
</tr>

<tr>
<td><code>alcohol</code></td>
<td>FLOAT</td>
</tr>

<tr>
<td><code>malic_acid</code></td>
<td>FLOAT</td>
</tr>

<tr>
<td><code>ash</code></td>
<td>FLOAT</td>
</tr>

<tr>
<td><code>alcalinity_of_ash</code></td>
<td>FLOAT</td>
</tr>

<tr>
<td><code>magnesium</code></td>
<td>INTEGER</td>
</tr>

<tr>
<td><code>total_phenols</code></td>
<td>FLOAT</td>
</tr>

<tr>
<td><code>flavanoids</code></td>
<td>FLOAT</td>
</tr>

<tr>
<td><code>nonflavanoid_phenols</code></td>
<td>FLOAT</td>
</tr>

<tr>
<td><code>proanthocyanins</code></td>
<td>FLOAT</td>
</tr>

<tr>
<td><code>color_intensity</code></td>
<td>FLOAT</td>
</tr>

<tr>
<td><code>hue</code></td>
<td>FLOAT</td>
</tr>

<tr>
<td><code>od280_or_od315_of_diluted_wines</code></td>
<td>FLOAT</td>
</tr>

<tr>
<td><code>proline</code></td>
<td>INTEGER</td>
</tr>
</tbody>
</table>
<p><strong>Output:</strong></p>

<table>
<thead>
<tr>
<th>Column</th>
<th>Type</th>
</tr>
</thead>

<tbody>
<tr>
<td><code>id</code></td>
<td>INTEGER</td>
</tr>
</tbody>
</table>


Let’s say you run a wine house. You have detailed information about the chemical composition of wines in a wines table.

SELECTive Wine Connoisseur

<p>Let’s say you work at Allstate. Allstate is running <code>N</code>  online ads right now. The table <code>ads</code> contains all those ads, ranked by popularity via the <code>id</code> column (e.g., the entry with <code>id = 1</code> is the most popular, etc.).</p>

<p>Create a subquery or common table expression named <code>top_ads</code> containing the top 3 ads (by popularity) and return the number of rows that would result from the following operations</p>

<ol>
<li><code>ads INNER JOIN top_ads</code></li>
<li><code>ads LEFT JOIN top_ads</code></li>
<li><code>ads RIGHT JOIN top_ads</code></li>
<li><code>ads CROSS JOIN top_ads</code></li>
</ol>

<p><em>Note: Please make the <code>join_type</code> column in your output have the values <code>inner_join</code>, <code>left_join</code>, etc. for each of their respective join types</em></p>

<p><em>Note: Please return only one query with each number in a different row</em></p>

<p><strong>Example:</strong></p>

<p><strong>Input:</strong></p>

<table>
<thead>
<tr>
<th>Column</th>
<th>Type</th>
</tr>
</thead>

<tbody>
<tr>
<td><code>id</code></td>
<td>INTEGER</td>
</tr>

<tr>
<td><code>name</code></td>
<td>VARCHAR</td>
</tr>
</tbody>
</table>
<p><strong>Output:</strong></p>

<table>
<thead>
<tr>
<th>Column</th>
<th>Type</th>
</tr>
</thead>

<tbody>
<tr>
<td><code>join_type</code></td>
<td>VARCHAR</td>
</tr>

<tr>
<td><code>number_of_rows</code></td>
<td>INTEGER</td>
</tr>
</tbody>
</table>


Create top_ads with the top 3 ads and return the row counts for inner, left, right, and cross joins with ads

Size of Joins

<p>Say you are tasked with designing a data mart or data warehouse for a new online retailer.</p>

<p>How would you design the system?</p>

<p><em>Note: Sketch a star schema to explain your design.</em></p>


<p>You have an array of integers, <code>nums</code> of length <code>n</code> spanning <code>0</code> to <code>n</code> with one missing. Write a function <code>missing_number</code> that returns the missing number in the array.</p>

<p><em>Note: Complexity of $O(n)$ required.</em></p>

<p><strong>Example:</strong></p>

<p><strong>Input:</strong></p>

<pre tabindex="0" class="chroma"><code><span class="line"><span class="cl"><span class="n">nums</span> <span class="o">=</span> <span class="p">[</span><span class="mi">0</span><span class="p">,</span><span class="mi">1</span><span class="p">,</span><span class="mi">2</span><span class="p">,</span><span class="mi">4</span><span class="p">,</span><span class="mi">5</span><span class="p">]</span> 
</span></span><span class="line"><span class="cl"><span class="n">missing_number</span><span class="p">(</span><span class="n">nums</span><span class="p">)</span> <span class="o">-&gt;</span> <span class="mi">3</span>
</span></span></code></pre>


<p>Tell me about a data project that didn’t go the way you expected. What did you set out to do, what surprised you, and how did you handle it?</p>


Describing a data project and its challenges

Hurdles In Data Projects

Behavioral

<p>Imagine a deck of 500 cards numbered from 1 to 500. If all the cards are shuffled randomly and you are asked to pick three cards, one at a time, what’s the probability of each subsequent card being larger than the previous drawn card?</p>


<p>Imagine a deck of 2000 cards numbered from 1 to 2000. If all the cards are shuffled randomly and you are asked to pick three cards, one at a time, what’s the probability of each subsequent card being larger than the previously drawn card?</p>


Imagine a deck of 2000 cards numbered from 1 to 2000. If all the cards are shuffled randomly and you are asked to pick three cards, one at a time, what's the probability of each subsequent card being larger than the previously drawn card?

2000 cards

<p>How would you explain what a p-value is to someone who is not technical?</p>


<p>What does a p-value in a statistical test represent?</p>

What does a p-value in a statistical test represent?

P-value to a Layman I

<p>In a statistical test, how does a low p-value (less than 0.05) influence our decision about the null hypothesis?</p>

In a statistical test, how does a low p-value (less than 0.05) influence our decision about the null hypothesis?

P-value to a Layman II

Explain what a p-value is to someone who is not technical

P-value to a Layman

Statistics

<p>Over budget on a project is defined when the salaries, prorated to the day, exceed the budget of the project.</p>

<p>For example, if Alice and Bob both combined income make 200K and work on a project of a budget of 50K that takes half a year, then the project is over budget given 0.5 * 200K = 100K &gt; 50K.</p>

<p>Write a query to forecast the budget for all projects and return a label of <code>&#34;overbudget&#34;</code> if it is over budget and <code>&#34;within budget&#34;</code> otherwise.</p>

<p><em>Note: Assume that employees only work on one project at a time.</em></p>

<p><strong>Example:</strong></p>

<p><strong>Input:</strong></p>

<p><code>employees</code> table</p>

<table>
<thead>
<tr>
<th>Column</th>
<th>Type</th>
</tr>
</thead>

<tbody>
<tr>
<td><code>id</code></td>
<td>INTEGER</td>
</tr>

<tr>
<td><code>first_name</code></td>
<td>VARCHAR</td>
</tr>

<tr>
<td><code>last_name</code></td>
<td>VARCHAR</td>
</tr>

<tr>
<td><code>salary</code></td>
<td>INTEGER</td>
</tr>

<tr>
<td><code>department_id</code></td>
<td>INTEGER</td>
</tr>
</tbody>
</table>
<p><code>projects</code> table</p>

<table>
<thead>
<tr>
<th>Column</th>
<th>Type</th>
</tr>
</thead>

<tbody>
<tr>
<td><code>id</code></td>
<td>INTEGER</td>
</tr>

<tr>
<td><code>title</code></td>
<td>VARCHAR</td>
</tr>

<tr>
<td><code>state_date</code></td>
<td>DATETIME</td>
</tr>

<tr>
<td><code>end_date</code></td>
<td>DATETIME</td>
</tr>

<tr>
<td><code>budget</code></td>
<td>INTEGER</td>
</tr>
</tbody>
</table>
<p><strong>departments</strong> table</p>

<table>
<thead>
<tr>
<th>Column</th>
<th>Type</th>
</tr>
</thead>

<tbody>
<tr>
<td><code>id</code></td>
<td>INTEGER</td>
</tr>

<tr>
<td><code>name</code></td>
<td>VARCHAR</td>
</tr>
</tbody>
</table>
<p><code>employee_projects</code> table</p>

<table>
<thead>
<tr>
<th>Column</th>
<th>Type</th>
</tr>
</thead>

<tbody>
<tr>
<td><code>project_id</code></td>
<td>INTEGER</td>
</tr>

<tr>
<td><code>employee_id</code></td>
<td>INTEGER</td>
</tr>
</tbody>
</table>
<p><strong>Output:</strong></p>

<table>
<thead>
<tr>
<th>Column</th>
<th>Type</th>
</tr>
</thead>

<tbody>
<tr>
<td><code>title</code></td>
<td>VARCHAR</td>
</tr>

<tr>
<td><code>project_forecast</code></td>
<td>VARCHAR</td>
</tr>
</tbody>
</table>


Write a query to forecast each project's budget and label it overbudget or within budget

Over-Budget Projects

<p>Let’s say you have a categorical variable with thousands of distinct values, how would you encode it?</p>


<p>Which method can be used to extract communities from large networks, that does not require a pre-determined number of clusters like K-means?</p>

Which method can be used to extract communities from large networks, that does not require a pre-determined number of clusters like K-means?

<p>Write a query to identify the manager with the biggest team size.</p>

<p>You may assume there is only one manager with the largest team size.</p>

<p><strong>Example:</strong></p>

<p><strong>Input:</strong></p>

<p><code>employees</code> table</p>

<table>
<thead>
<tr>
<th>Column</th>
<th>Type</th>
</tr>
</thead>

<tbody>
<tr>
<td><code>id</code></td>
<td>INTEGER</td>
</tr>

<tr>
<td><code>name</code></td>
<td>VARCHAR</td>
</tr>

<tr>
<td><code>manager_id</code></td>
<td>INTEGER</td>
</tr>
</tbody>
</table>
<p><code>managers</code> table</p>

<table>
<thead>
<tr>
<th>Column</th>
<th>Type</th>
</tr>
</thead>

<tbody>
<tr>
<td><code>id</code></td>
<td>INTEGER</td>
</tr>

<tr>
<td><code>name</code></td>
<td>VARCHAR</td>
</tr>

<tr>
<td><code>team</code></td>
<td>VARCHAR</td>
</tr>
</tbody>
</table>
<p><strong>Output:</strong></p>

<table>
<thead>
<tr>
<th>Column</th>
<th>Type</th>
</tr>
</thead>

<tbody>
<tr>
<td><code>manager</code></td>
<td>VARCHAR</td>
</tr>

<tr>
<td><code>team_size</code></td>
<td>INTEGER</td>
</tr>
</tbody>
</table>


Manager Team Sizes

<p>Given a table of <code>transactions</code> and <code>products</code>, write a function to get the <code>month_over_month</code> change in revenue for the year 2019. Make sure to round <code>month_over_month</code> to 2 decimal places.</p>

<p><strong>Example:</strong></p>

<p><strong>Input:</strong></p>

<p><code>transactions</code> table</p>

<table>
<thead>
<tr>
<th>Column</th>
<th>Type</th>
</tr>
</thead>

<tbody>
<tr>
<td><code>id</code></td>
<td>INTEGER</td>
</tr>

<tr>
<td><code>user_id</code></td>
<td>INTEGER</td>
</tr>

<tr>
<td><code>created_at</code></td>
<td>DATETIME</td>
</tr>

<tr>
<td><code>product_id</code></td>
<td>INTEGER</td>
</tr>

<tr>
<td><code>quantity</code></td>
<td>INTEGER</td>
</tr>
</tbody>
</table>
<p><code>products</code> table</p>

<table>
<thead>
<tr>
<th>Column</th>
<th>Type</th>
</tr>
</thead>

<tbody>
<tr>
<td><code>id</code></td>
<td>INTEGER</td>
</tr>

<tr>
<td><code>name</code></td>
<td>VARCHAR</td>
</tr>

<tr>
<td><code>price</code></td>
<td>FLOAT</td>
</tr>
</tbody>
</table>
<p><strong>Output:</strong></p>

<table>
<thead>
<tr>
<th>Column</th>
<th>Type</th>
</tr>
</thead>

<tbody>
<tr>
<td><code>month</code></td>
<td>INTEGER</td>
</tr>

<tr>
<td><code>month_over_month</code></td>
<td>FLOAT</td>
</tr>
</tbody>
</table>


Write a function to get the month_over_month change in revenue for 2019 rounded to 2 decimal places

Month Over Month

<p>Given a table with event logs, find the top five users with the longest continuous streak of visiting the platform.</p>

<p><em>Note: A continuous streak counts if the user visits the platform at least once per day on consecutive days.</em></p>

<p><strong>Example:</strong></p>

<p><strong>Input:</strong></p>

<p><code>events</code> table</p>

<table>
<thead>
<tr>
<th><code>Column</code></th>
<th><code>Type</code></th>
</tr>
</thead>

<tbody>
<tr>
<td><code>user_id</code></td>
<td>INTEGER</td>
</tr>

<tr>
<td><code>created_at</code></td>
<td>DATETIME</td>
</tr>

<tr>
<td><code>url</code></td>
<td>VARCHAR</td>
</tr>
</tbody>
</table>
<p><strong>Output:</strong></p>

<table>
<thead>
<tr>
<th><code>Column</code></th>
<th><code>Type</code></th>
</tr>
</thead>

<tbody>
<tr>
<td><code>user_id</code></td>
<td>INTEGER</td>
</tr>

<tr>
<td><code>streak_length</code></td>
<td>INTEGER</td>
</tr>
</tbody>
</table>


Longest Streak Users

<p>Write a Python function called <strong><code>max_profit</code></strong> that takes a list of integers, where the i-th integer represents the price of a given stock on day i, and returns the maximum profit you can achieve by buying and selling the stock.</p>

<p>You may complete, at most, two complete buy/sell transactions to maximize profits on a stock.</p>

<p><strong>Input:</strong></p>

<pre tabindex="0" class="chroma"><code><span class="line"><span class="cl"><span class="n">prices</span> <span class="o">=</span> <span class="p">[</span><span class="mi">3</span><span class="p">,</span> <span class="mi">3</span><span class="p">,</span> <span class="mi">5</span><span class="p">,</span> <span class="mi">0</span><span class="p">,</span> <span class="mi">0</span><span class="p">,</span> <span class="mi">3</span><span class="p">,</span> <span class="mi">1</span><span class="p">,</span> <span class="mi">4</span><span class="p">]</span>
</span></span></code></pre>

<p><strong>Output:</strong></p>

<pre tabindex="0" class="chroma"><code><span class="line"><span class="cl"><span class="k">def</span> <span class="nf">max_profit</span><span class="p">(</span><span class="n">prices</span><span class="p">)</span> <span class="o">-&gt;</span> <span class="mi">6</span>
</span></span></code></pre>

<p>Explanation:</p>

<pre><code>Buy on day 4 (price = 0) and sell on day 6 (price = 3): profit = 3 - 0 = 3.
Then buy again on day 7 (price = 1) and sell on day 8 (price = 4): profit = 4 - 1 = 3.
Total profit: 3 + 3 = 6.
</code></pre>


Find the maximum profit from at most two stock buy/sell transactions

Maximum Profit

<p>Let’s say we have two tables, <code>transactions</code> and <code>products</code>. Hypothetically the <code>transactions</code> table consists of over a billion rows of purchases bought by users.</p>

<p>We are trying to find paired products that are often purchased together by the same user, such as wine and bottle openers, chips and beer, etc..</p>

<p>Write a query to find the top five paired products and their names.</p>

<p><em>Notes:</em>
   <em>For the purposes of satisfying the test case, p2 should be the item that comes first in the alphabet.</em>
   <em>The <code>qty</code> column represents paired products count</em></p>

<p><strong>Example:</strong></p>

<p><strong>Input:</strong></p>

<p><code>transactions</code> table</p>

<table>
<thead>
<tr>
<th>Column</th>
<th>Type</th>
</tr>
</thead>

<tbody>
<tr>
<td><code>id</code></td>
<td>INTEGER</td>
</tr>

<tr>
<td><code>user_id</code></td>
<td>INTEGER</td>
</tr>

<tr>
<td><code>created_at</code></td>
<td>DATETIME</td>
</tr>

<tr>
<td><code>product_id</code></td>
<td>INTEGER</td>
</tr>

<tr>
<td><code>quantity</code></td>
<td>INTEGER</td>
</tr>
</tbody>
</table>
<p><code>products</code> table</p>

<table>
<thead>
<tr>
<th>Column</th>
<th>Type</th>
</tr>
</thead>

<tbody>
<tr>
<td><code>id</code></td>
<td>INTEGER</td>
</tr>

<tr>
<td><code>name</code></td>
<td>VARCHAR</td>
</tr>

<tr>
<td><code>price</code></td>
<td>FLOAT</td>
</tr>
</tbody>
</table>
<p><strong>Output:</strong></p>

<table>
<thead>
<tr>
<th>Column</th>
<th>Type</th>
</tr>
</thead>

<tbody>
<tr>
<td><code>p1</code></td>
<td>VARCHAR</td>
</tr>

<tr>
<td><code>p2</code></td>
<td>VARCHAR</td>
</tr>

<tr>
<td><code>qty</code></td>
<td>INTEGER</td>
</tr>
</tbody>
</table>


Paired Products

<p>There are two tables. One table is called <code>swipes</code> that holds a row for every Tinder swipe and contains a boolean column that determines if the swipe was a right or left swipe called <code>is_right_swipe</code>. The second is a table named <code>variants</code> that determines which user has which variant of an AB test.</p>

<p>Write a SQL query to output the average number of right swipes for two different variants of a feed ranking algorithm by comparing users that have swiped 10, 50, and 100 swipes in a <code>feed_change</code> experiment.</p>

<p><em>Note: Users have to have swiped at least 10 times to be included in the subset of users to analyze the mean number of right swipes.</em></p>

<p><strong>Example:</strong></p>

<p><strong>Input:</strong></p>

<p><code>variants</code> table</p>

<table>
<thead>
<tr>
<th>Columns</th>
<th>Type</th>
</tr>
</thead>

<tbody>
<tr>
<td><code>id</code></td>
<td>INTEGER</td>
</tr>

<tr>
<td><code>experiment</code></td>
<td>VARCHAR</td>
</tr>

<tr>
<td><code>variant</code></td>
<td>VARCHAR</td>
</tr>

<tr>
<td><code>user_id</code></td>
<td>INTEGER</td>
</tr>
</tbody>
</table>
<p><code>swipes</code> table</p>

<table>
<thead>
<tr>
<th>Columns</th>
<th>Type</th>
</tr>
</thead>

<tbody>
<tr>
<td><code>id</code></td>
<td>INTEGER</td>
</tr>

<tr>
<td><code>user_id</code></td>
<td>INTEGER</td>
</tr>

<tr>
<td><code>swiped_user_id</code></td>
<td>INTEGER</td>
</tr>

<tr>
<td><code>created_at</code></td>
<td>DATETIME</td>
</tr>

<tr>
<td><code>is_right_swipe</code></td>
<td>BOOLEAN</td>
</tr>
</tbody>
</table>
<p><strong>Output:</strong></p>

<table>
<thead>
<tr>
<th>Columns</th>
<th>Type</th>
</tr>
</thead>

<tbody>
<tr>
<td><code>variant</code></td>
<td>VARCHAR</td>
</tr>

<tr>
<td><code>mean_right_swipes</code></td>
<td>FLOAT</td>
</tr>

<tr>
<td><code>swipe_threshold</code></td>
<td>INTEGER</td>
</tr>

<tr>
<td><code>num_users</code></td>
<td>INTEGER</td>
</tr>
</tbody>
</table>


Write a SQL query to find the average number of right swipes for different ranking algorithms.

Swipe Precision

Challenge

<h3>Job Description</h3><div>Job Description<div><p><strong>Job Title:</strong> Lead Business Intelligence Analyst<b> <strong>Location:</strong> Irvine, California<b> <strong>Type:</strong> Contract<b> <strong>Compensation: </strong>$84-89.23/hr<b> <strong>Work Model:</strong> Onsite <b> <strong>Hours:</strong> 40.0</b></b></b></b></b></p><p><b> <strong>Responsibilities</strong></b></p><ul><li>Responsible for leading the design and support of commercial business intelligence applications and architecture. </li><li>Works with commercial / sales ops business partners to understand and prioritize data and information requirements. </li><li>Solves complex technical problems. </li><li>Optimizes the performance of business intelligence tools by defining data to filter and index that add value to the user. </li><li>Creates testing methodology and criteria. </li><li>Designs and coordinates a curriculum for coaching and training customers in the use of business intelligence tools to enhance business decision-making capability. </li><li>Develops standards, policies and procedures for the form, structure and attributes of the business intelligence tools and systems. </li><li>Develops data/information quality metrics. </li><li>Researches new technology and develops business cases to support enterprise wide business intelligence solutions. </li><li>Adapts precedent and may make significant departures from traditional approaches to develop solutions. </li></ul><p><b> <strong>Requirements</strong></b></p><ul><li>Completed degree with minimum of 4 or more years experience </li></ul><p>System One, and its subsidiaries including Joulé and Mountain Ltd., are leaders in delivering outsourced services and workforce solutions across North America. We help clients get work done more efficiently and economically, without compromising quality. System One not only serves as a valued partner for our clients, but we offer eligible employees health and welfare benefits coverage options including medical, dental, vision, spending accounts, life insurance, voluntary plans, as well as participation in a 401(k) plan.</p><p>System One is an Equal Opportunity Employer. All qualified applicants will receive consideration for employment without regard to race, color, religion, sex (including pregnancy, childbirth, or related medical conditions), sexual orientation, gender identity, age, national origin, disability, family care or medical leave status, genetic information, veteran status, marital status, or any other characteristic protected by applicable federal, state, or local law.</p><p></p><b> <b>Ref: #558-Scientific<p><b></b></p></b></b></div></div>

<h3>Job Description</h3><div>Job Description<div><p>Job Title: Senior Business Intelligence Analyst<b> Location: Hybrid Reporting to Vienna, VA, Pensacola, FL, or Winchester, VA<b> Type: Contract</b></b></p><p>Responsibilities</p><ul><li>Support business decisions within the Digital department by providing quantitative and qualitative data analysis, reporting, and insights that evaluate the performance of new digital enhancements and help steward the overall experience and performance of the organization's mobile and online applications, as well as employee-facing experience products.</li><li>Collect, aggregate, and analyze data from multiple internal and external sources, including structured and unstructured data sets, to drive insights into digital performance, member behavior, employee experience, and business outcomes.</li><li>Communicate findings and insights to stakeholders and provide business strategy recommendations for optimizing digital performance, adoption, containment, self-service, and experience outcomes.</li><li>Develop, maintain, and manage advanced reporting, dashboards, scorecards, and BI solutions that monitor the health, adoption, effectiveness, and operational performance of mobile, online, and employee-facing digital products.</li><li>Evaluate new digital enhancements before and after release by defining success measures, establishing baselines, monitoring adoption and performance, and identifying usability, journey, or experience opportunities.</li><li>Identify, analyze, and interpret trends or patterns across digital journeys and prepare ongoing reports and data visualizations, including charts, dashboards, heat maps, funnels, and scorecards, to support business decisions.</li><li>Produce actionable reports that show key performance indicators, identify areas of improvement in current operations, and display root cause analysis of digital performance or experience issues.</li><li>Use analytics and metrics to improve processes and provide data-driven forecasts of potential costs, risks, member impacts, employee impacts, and benefits of new business or digital initiatives.</li><li>Understand data gaps and connect data components across systems to support reliable reporting, visualization, and digital product performance measurement.</li><li>Provide reporting solutions and respond to ad-hoc report requests across Digital and partner business areas, including Product, Marketing, Contact Center Operations, IT, Member Service Operations, and Risk partners as appropriate.</li><li>Create specifications for reports, analysis, dashboards, and measurement plans based on business needs, product objectives, digital release plans, and required or available data elements.</li><li>Assist with the development and enhancement of practices, procedures, data definitions, measurement standards, and documentation that improve consistency across Digital reporting.</li><li>Develop and maintain strong working relationships with team members, subject matter experts, product owners, journey owners, and leaders; work with senior management on complex issues as needed.</li><li>Lead small to medium projects and support larger initiatives that improve Digital BI capabilities, strengthen performance management, or advance digital experience measurement.</li><li>Provide guidance to lower level staff on analytic methods, dashboard design, stakeholder communication, and root cause analysis.</li><li>Manage a portfolio of dashboards and analytic products, monitor usage and performance, and make recommendations to management for enhancements, retirements, or governance changes.</li></ul> Requirements <ul><li>7+ years of experience in data analysis, business intelligence, reporting, or digital analytics.</li><li>Advanced skill using business intelligence applications and/or cloud services to develop reporting, dashboards, and analytic solutions.</li><li>Advanced knowledge of reporting capabilities from enterprise data platforms, ERP, CRM, digital analytics, product analytics, or database software vendors.</li><li>Advanced skill using statistical methods, mathematical techniques, forecasting, cost-benefit analysis, experiment measurement, and root cause analysis.</li><li>Advanced skill with data analysis tools and programming languages such as Python, R, SQL, or comparable analytic tools.</li><li>Advanced knowledge of reporting and dashboarding best practices, data storytelling, data visualization, data research, and root cause analysis techniques.</li><li>Strong stakeholder management skills, with demonstrated ability to influence business partners and translate complex analysis into clear recommendations.</li><li>Advanced knowledge of data integration, data quality, cleaning, validation, metadata, and measurement governance techniques.</li><li>Advanced research skills, including the ability to complete data research, business research, reporting and dashboarding best practices research, needs assessments, and digital performance analysis.</li><li>Strong interpersonal, facilitation, and communication skills, with the ability to collaborate across technical and non-technical audiences.</li></ul><p><b> <b> System One, and its subsidiaries including Joulé and Mountain Ltd., are leaders in delivering outsourced services and workforce solutions across North America. We help clients get work done more efficiently and economically, without compromising quality. System One not only serves as a valued partner for our clients, but we offer eligible employees health and welfare benefits coverage options including medical, dental, vision, spending accounts, life insurance, voluntary plans, as well as participation in a 401(k) plan.<b> <b> <b> System One is an Equal Opportunity Employer. All qualified applicants will receive consideration for employment without regard to race, color, religion, sex (including pregnancy, childbirth, or related medical conditions), sexual orientation, gender identity, age, national origin, disability, family care or medical leave status, genetic information, veteran status, marital status, or any other characteristic protected by applicable federal, state, or local law.<b> <b> #M-<b> #LI-</b></b></b></b></b></b></b></b></p><p><b></b></p></div></div>

<h3>Job Description</h3><div>Job Description<div><p><strong>Job Title:</strong> Data Scientist<b> <strong>Location:</strong> McLean, VA (onsite)<b> <strong>Type:</strong> Contract<b> <strong>Compensation:</strong> $104.71/HR on W2<b> <strong>Clearance:</strong> TS/SCI w/ CI Poly<b> <b> Responsibilities</b></b></b></b></b></b></p><ul><li>Recommend survey design, testing, and administration across multiple platforms. </li><li>Assist customers in identifying suitable survey tools on various platforms. </li><li>Offer expert support in methodological, technological, and ethical aspects (e.g., ensuring neutrality, precision, and repeatability of measures; conducting cost-benefit analyses of survey tools; and maintaining respondent anonymity). </li><li>Ensure accessibility and accuracy of surveys by resolving technical issues pre-launch. </li><li>Manage survey administration and monitor and resolve all technical issues, including accessibility problems, across platforms during the survey period. </li><li>Consolidate data and provide integrated data analysis of survey results. </li><li>Compile and organize element-specific free text responses and run AI/LLM tools with multiple prompts to confirm human review of the free text comments. </li><li>Develop and present survey findings through appropriate visualization techniques and recommend presentation formats (e.g., scatter charts, donut charts, stacked column charts) to effectively communicate findings to senior management. </li><li>Develop customized briefing materials and presentations featuring aggregate data, element specific data, and content for key stakeholders. </li></ul> Requirements <ul><li>Top Secret/Sensitive Compartmented Information (TS/SCI) clearance with Polygraph. </li><li>Typically requires BS degree and 8 – 12 years of prior relevant experience or Masters with 6 – 10 years of prior relevant experience. </li><li>Expertise in survey tools and software (e.g., LimeSurvey). </li><li>Expertise with survey data analysis methodologies and tools (Tableau, Microsoft Excel, IBM SPSS), quantitative methods, and data visualization techniques. </li><li>Experience in providing advisement on intelligence products and processes. </li></ul><p>System One, and its subsidiaries including Joulé and Mountain Ltd., are leaders in delivering outsourced services and workforce solutions across North America. We help clients get work done more efficiently and economically, without compromising quality. System One not only serves as a valued partner for our clients, but we offer eligible employees health and welfare benefits coverage options including medical, dental, vision, spending accounts, life insurance, voluntary plans, as well as participation in a 401(k) plan.</p><p>System One is an Equal Opportunity Employer. All qualified applicants will receive consideration for employment without regard to race, color, religion, sex (including pregnancy, childbirth, or related medical conditions), sexual orientation, gender identity, age, national origin, disability, family care or medical leave status, genetic information, veteran status, marital status, or any other characteristic protected by applicable federal, state, or local law.</p><p>#M-M2<b> #LI-RF1</b></p><b> <b>Ref: #851-Rockville-S1<p><b></b></p></b></b></div></div>

<h3>Job Description</h3><div>Job Description<div>Job Title: Business Analyst- RESTful API <b> Location: Dallas, Texas, United States <b> Job Type: Permanent Full Time <b> <b> Description: <b> <b> Business Analyst- RESTful API <b> <b> Position Description <b> We are seeking a skilled Business Analyst to support a backend engineering team that designs and builds RESTful APIs in a large e commerce environment supporting our client's customer facing applications. This role partners closely with Product Owners, Engineers, QE, and DevOps to translate business needs into clear, testable requirements that drive scalable, <span class="long-word">cloud?containerized</span> and cloud native services. <b> <b> <b> Your future duties and responsibilities <b> . Analyze business and technical requirements and write high quality user stories for backend RESTful services <b> . Define functional and non functional requirements, including performance, security, scalability, and observability <b> . Break down epics into well defined, testable stories with clear acceptance criteria including what can be automated for testing. <b> . Grasp upstream and downstream dependencies and system architecture to sequence work most efficiently <b> . Review and validate API contracts (OpenAPI/Swagger) to ensure clarity and alignment with business intent <b> . Support API testing and validation using tools like Postman <b> . Review logs, analyze and troubleshoot errors <b> . Participate in Agile ceremonies and support delivery through testing, defect triage, and release readiness <b> . Collaborate with backend engineers, QE, DevOps, and downstream partners across integrated systems <b> <b> <b> Required qualifications to be successful in this role <b> . Experience as a Business Analyst supporting backend or API centric teams <b> . Hands on experience with API testing and ability to understand API contracts is required <b> . Strong understanding of RESTful API design and integration patterns <b> . Working familiarity with AWS cloud concepts and services (e.g., API Gateway, Lambda, CloudWatch, IAM) <b> . Experience working in Agile/Scrum environments <b> . Strong analytical, documentation, and communication skills <b> . Curious mindset with ability to use AI tools with increasing efficiency <b> . Airline domain experience preferred <b><p><b></b></p></b></b></b></b></b></b></b></b></b></b></b></b></b></b></b></b></b></b></b></b></b></b></b></b></b></b></b></b></b></b></b></b></b></div></div>

<h3>Job Description</h3><div>Job Description<div><p><strong>Job Title: </strong>Senior Associate Research Scientist I<b> <strong>Location:</strong> Durham, NC<b> <strong>Type: </strong>Contract<b> <strong>Compensation:</strong> $30 - $35/hr<b> <strong>Work Model: </strong>Onsite</b></b></b></b></p><p><strong>Responsibilities</strong></p><ul><li>Provide analytical testing support for development and process characterization projects. </li><li>Perform analytical testing and analyses using modern instrumental analytical techniques, including Karl Fischer moisture analysis, coagulation assays, enzymatic assays, and immunoassays. </li><li>Operate and maintain analytical instruments such as coulometric titrator, coagulation analyzer, <span class="long-word">immunonephelometer,</span> and plate readers. </li><li>Document laboratory work accurately and contemporaneously in research notebooks or LIMS systems; contribute to report writing as needed. </li><li>Identify aberrant results, initiate investigations, and participate in problem-solving efforts independently. </li><li>Demonstrate strong organizational, attention to detail, and excellent verbal and written communication skills. </li><li>Maintain compliance with cGXP environment standards and regulatory guidance documents related to test methods and CMC development. </li><li>Perform moderate lifting of 15-30 lbs. with a maximum of 35 lbs., and work in an environment exposing to biological fluids, chemicals, and electrical equipment. </li></ul><strong>Requirements</strong><ul><li>Degree in Biology, Biochemistry, Chemistry, or Toxicology (Master’s preferred with 1+ years experience or Bachelor’s with 3-4 years relevant experience). </li><li>Relevant analytical test experience in a cGXP environment, including proper pipetting techniques and knowledge of regulatory guidance. </li><li>Experience operating and maintaining analytical instruments such as coulometric titrators, coagulation analyzers, <span class="long-word">immunonephelometers,</span> and plate readers. </li><li>Proficiency in MS Office applications. </li><li>Ability to perform detailed documentation and report writing. </li><li>Strong organizational, communication, and problem-solving skills. </li><li>Ability to work in a <span class="long-word">clinical/laboratory</span> environment with exposure to biological fluids, chemicals, and electrical equipment. </li></ul><p>System One, and its subsidiaries including Joulé and Mountain Ltd., are leaders in delivering outsourced services and workforce solutions across North America. We help clients get work done more efficiently and economically, without compromising quality. System One not only serves as a valued partner for our clients, but we offer eligible employees health and welfare benefits coverage options including medical, dental, vision, spending accounts, life insurance, voluntary plans, as well as participation in a 401(k) plan.</p><p>System One is an Equal Opportunity Employer. All qualified applicants will receive consideration for employment without regard to race, color, religion, sex (including pregnancy, childbirth, or related medical conditions), sexual orientation, gender identity, age, national origin, disability, family care or medical leave status, genetic information, veteran status, marital status, or any other characteristic protected by applicable federal, state, or local law.</p><p><b> Ref: #558-Scientific</b></p><p><b></b></p></div></div>

<h3>Job Description</h3><div>Job Description<div><p><strong>Data Analyst </strong><b> <strong>12 Month+ Contract </strong><b> <strong>Hybrid – 3 Days/wk on-site in either Vienna, VA/Winchester, VA/ or Pensacola, FL </strong><b> <strong>Hourly Rate: $60/hr. range, W2. Benefits available<b> On-Site Interview Expected</b></strong><b> <b> System One IT has a 12-month+ contract opening for a Data Analyst to support a leading financial services customer. <b> <b> <strong>Must have: </strong></b></b></b></b></b></b></b></p><ul><li>SQL - needed to pull tables and associated data elements/columns. </li><li><span class="long-word">Organization/project</span> <span class="long-word">management/reporting</span> - needed to provide stakeholders updates on progress and ensure full inventory is reviewed and captured. </li><li>Knowledge of data governance practices (creating data dictionaries, sttms, cdes) </li><li>Working in teams - this project cannot be done in a silo and will require peer and stakeholder support. </li></ul><b> <strong>Nice to have: </strong><ul><li>Power BI experience </li><li>Executive presentations </li><li>Translating data trends into insights </li></ul><b> <strong>DESCRIPTION</strong> <b> This mid-level Data Analyst will lead the remediation of a large data governance backlog, with a primary focus on identifying priority tables and developing the governance artifacts needed to make those tables understandable, trusted, and reusable. The role will produce and coordinate artifacts such as data dictionaries, source-to-target mappings (STTM), critical data element (CDE) documentation, lineage context, and related metadata documentation. The analyst will work with governance partners, data owners, internal analyst teams, and subject matter experts to accelerate backlog clean-up while preserving quality, traceability, and business usability. <b> The successful candidate will combine strong SQL and analytical skills with disciplined project management and clear stakeholder communication. They will help democratize clean and governed tables for broader enterprise use, enabling business units to confidently benefit from internally warehoused data. Power BI experience is strongly preferred, particularly the ability to visualize remediation plans, progress, risks, and outcomes. Upon successful completion of the governance backlog, there may be an opportunity for the role to evolve into a more business-intelligence-oriented position, depending on demonstrated capabilities in Power BI, SQL, and data storytelling. <b> <b> <strong>RESPONSIBILITIES</strong><ul><li>Lead the end-to-end remediation plan for a large data governance backlog, including intake, prioritization, sequencing, status tracking, risk identification, and follow-through on deliverables. </li><li>Identify and prioritize key tables that require governance artifacts based on usage, business value, data sensitivity, reporting dependency, and readiness for broader enterprise consumption. </li><li>Create, validate, and maintain data dictionaries, source-to-target mappings (STTM), CDE documentation, metadata, lineage context, and related governance artifacts. </li><li>Use SQL to profile, validate, investigate, and document tables, fields, transformations, joins, business rules, and data quality considerations. </li><li>Partner with data governance teams to align deliverables with enterprise standards, metadata expectations, cataloging requirements, CDE practices, and artifact approval workflows. </li><li>Collaborate with internal analyst teams and subject matter experts who possess unique knowledge of business processes, table usage, definitions, and reporting dependencies. </li><li>Translate technical findings into clear, concise updates for stakeholders, including progress summaries, blockers, decisions needed, risks, dependencies, and recommended next steps. </li><li>Support democratization of clean, governed, well-documented tables so other business units can understand, discover, and use internally warehoused data appropriately. </li><li>Develop and maintain reporting or dashboard views, preferably in Power BI, to visualize remediation progress, backlog burn-down, artifact completeness, data readiness, and adoption opportunities. </li><li>Recommend improvements to documentation templates, governance intake processes, quality checks, and repeatable workflows that increase efficiency and reduce manual rework. </li><li>Ensure documentation is business-friendly, technically accurate, and usable by analysts, data stewards, governance partners, and leadership audiences. </li><li>Contribute to analytics and business intelligence work as backlog remediation matures, including dashboard requirements, data modeling support, visualization design, and storytelling with governed data. </li><li>Perform other duties as assigned. </li></ul><b> <strong>QUALIFICATIONS</strong><ul><li>Significant experience researching, compiling, documenting, and validating data, business processes, data flows, and analytical workflows. </li><li>Advanced SQL skills, including the ability to query large datasets, assess table structures, validate field logic, investigate data quality issues, and interpret joins or transformations. </li><li>Demonstrated ability to manage complex workstreams with multiple stakeholders, dependencies, deadlines, deliverables, and quality expectations. </li><li>Experience creating or maintaining data dictionaries, metadata documentation, source-to-target mappings, data lineage notes, business definitions, or similar governance artifacts. </li><li>Working knowledge of data governance concepts, including metadata management, CDEs, data stewardship, data ownership, data quality, and governed data access. </li><li>Working knowledge of data warehousing concepts, database structures, ETL/ELT processes, and analytical data pipelines. </li><li>Strong communication skills with the ability to summarize technical findings, explain documentation needs, escalate blockers, and communicate progress to both technical and business audiences. </li><li>Advanced skill in identifying business requirements, clarifying data definitions, resolving ambiguity, and recommending practical solutions. </li><li>Ability to partner effectively with governance teams, analysts, data owners, engineers, and business stakeholders to collect, validate, and publish high-quality documentation. </li><li>Advanced skill in interpreting data models, tables, reports, and documentation and translating them into formats that support decision-making and enterprise reuse. </li><li>Experience with project tracking, issue management, status reporting, and documentation quality control. </li><li>Advanced Microsoft Excel skills and familiarity with collaboration tools used to manage inventories, deliverables, status updates, and documentation review cycles. </li><li>Bachelor's degree in Information Systems, Computer Science, Engineering, Business Analytics, Data Analytics, or a related field, or the equivalent combination of training, education, and experience. </li></ul><b> <strong>DESIRED QUALIFICATIONS</strong><ul><li>Power BI experience, including the ability to create dashboards that communicate plan, progress, risk, backlog burn-down, artifact completion, and adoption readiness. </li><li>Experience applying data storytelling principles to turn governed data into leadership-ready insights, decisions, and recommendations. </li><li>Experience with Microsoft Purview or similar data catalog, metadata management, or governance platforms. </li><li>Experience supporting enterprise-wide or cross-business unit data governance, reporting, analytics, or documentation initiatives. </li><li>Familiarity with semantic models, curated datasets, certified data products, self-service BI enablement, or analyst adoption programs. </li><li>PMP certification, Agile certification, or commensurate experience managing cross-functional projects or enterprise workstreams. </li><li>Advanced degree in Information Systems, Computer Science, Engineering, Business Analytics, Data Analytics, or a related field. </li></ul><p>System One, and its subsidiaries including Joulé and Mountain Ltd., are leaders in delivering outsourced services and workforce solutions across North America. We help clients get work done more efficiently and economically, without compromising quality. System One not only serves as a valued partner for our clients, but we offer eligible employees health and welfare benefits coverage options including medical, dental, vision, spending accounts, life insurance, voluntary plans, as well as participation in a 401(k) plan.</p><p>System One is an Equal Opportunity Employer. All qualified applicants will receive consideration for employment without regard to race, color, religion, sex (including pregnancy, childbirth, or related medical conditions), sexual orientation, gender identity, age, national origin, disability, family care or medical leave status, genetic information, veteran status, marital status, or any other characteristic protected by applicable federal, state, or local law.</p><p>#M-MM1<b> #LI-MM1</b></p><b> <b>Ref: #851-Rockville-S1<p><b></b></p></b></b></b></b></b></b></b></b></b></b></div></div>

<h3>Job Description</h3><div>Job Description<div><p><strong>Data Risk Analyst<b> Location: Pensacola, FL (Hybrid) <b> Pay Rate: $60/hr. W2. Benefits available<b> Position Type: Contract</b></b></b></strong><b> <b> Our client is seeking a detail-oriented and analytical Data Risk Analyst to join the Data Risk Governance team within the Human Resources (HR) Risk Office. In this role, you will help identify, assess, and mitigate risks related to data classification, data privacy, data quality, data use, and regulatory compliance. You will support the implementation of governance frameworks that ensure effective data risk management across the enterprise.<b> <b> <strong>Key Responsibilities:</strong></b></b></b></b></p><ul><li>Support the HR Manager and Managing Data Steward in assigned tasks related to established procedures, such as Data Transfer Authorizations. </li><li>Collaborate with business and IT stakeholders to identify data risks and recommend appropriate mitigation strategies. </li><li>Assist in the development and maintenance of data governance policies, standards, and procedures. </li><li>Monitor compliance with internal data policies and external regulatory requirements (e.g., Enterprise Data Governance and Information Security instructions and standards, GDPR, CCPA, HIPAA, etc.). </li><li>Support risk reporting by analyzing data and producing dashboards, scorecards, and executive summaries, as requested. </li><li>Participate in data incident investigations, root cause analyses, and remediation tracking. </li><li>Work with data stewards, data owners, legal, and compliance teams to promote awareness and accountability for data risk. </li><li>Maintain a register of data risks and control gaps and ensure timely follow-up and resolution. </li><li>Stay up-to-date on emerging data risks, industry best practices, and regulatory changes. </li><li>Contribute to continuous improvement of data risk documentation, assessments, and control evaluation processes. </li></ul><b> <strong>Qualifications:</strong><ul><li>Bachelor’s degree in Data Science, Risk Management, Information Systems, Business, or related field. </li><li>5+ years of experience in risk management, data governance, audit, or compliance; experience with data risk preferred. </li><li>Strong understanding of data risk concepts, including privacy, quality, security, and ethical use of data. </li><li>Familiarity with regulatory requirements such as GDPR, CCPA, SOX, or industry-specific standards. </li><li>Strong analytical mindset with proficiency in Excel, Power BI, Tableau, or similar tools. </li><li>Excellent communication and interpersonal skills; ability to translate complex issues for non-technical audiences. </li><li>Experience with GRC tools (e.g., Archer, OneTrust, LogicGate, ServiceNow) is a plus. </li><li>Ability to work independently and collaboratively in a fast-paced, evolving environment. </li></ul><b> <strong><span class="long-word">Preferred/Desirable</span> Certifications:</strong><ul><li>Certified Data Privacy Solutions Engineer (CDPSE) </li><li>Certified Information Privacy Professional (CIPP) </li><li>Certified Risk and Information Systems Control (CRISC) </li><li>DAMA Certified Data Management Professional (CDMP) </li><li>Experience with the organization's Policies and Procedures </li></ul><p><b> System One, and its subsidiaries including Joulé and Mountain Ltd., are leaders in delivering outsourced services and workforce solutions across North America. We help clients get work done more efficiently and economically, without compromising quality. System One not only serves as a valued partner for our clients, but we offer eligible employees health and welfare benefits coverage options including medical, dental, vision, spending accounts, life insurance, voluntary plans, as well as participation in a 401(k) plan.</b></p><p>System One is an Equal Opportunity Employer. All qualified applicants will receive consideration for employment without regard to race, color, religion, sex (including pregnancy, childbirth, or related medical conditions), sexual orientation, gender identity, age, national origin, disability, family care or medical leave status, genetic information, veteran status, marital status, or any other characteristic protected by applicable federal, state, or local law.</p><p>#M- MM1<b> #LI- MM1<b> Ref: #851-Rockville-S1</b></b></p><p><b></b></p></b></b></div></div>

<h3>Job Description</h3><div>Job Description<div><p>Job Title: Mid-Level Business Intelligence Analyst<b> Location: Hybrid Reporting to Vienna, VA, Pensacola, FL, or Winchester, VA<b> Type: Contract</b></b></p><p>Responsibilities</p><ul><li>Support business decisions within the Digital department by providing quantitative and qualitative data analysis, reporting, and insights that evaluate the performance of new digital enhancements and help steward the overall experience and performance of the organization's mobile and online applications, as well as employee-facing experience products.</li><li>Collect, aggregate, and analyze data from multiple internal and external sources, including structured and unstructured data sets, to drive insights into digital performance, member behavior, employee experience, and business outcomes.</li><li>Communicate findings and insights to stakeholders and provide business strategy recommendations for optimizing digital performance, adoption, containment, self-service, and experience outcomes.</li><li>Develop, maintain, and manage advanced reporting, dashboards, scorecards, and BI solutions that monitor the health, adoption, effectiveness, and operational performance of mobile, online, and employee-facing digital products.</li><li>Evaluate new digital enhancements before and after release by defining success measures, establishing baselines, monitoring adoption and performance, and identifying usability, journey, or experience opportunities.</li><li>Identify, analyze, and interpret trends or patterns across digital journeys and prepare ongoing reports and data visualizations, including charts, dashboards, heat maps, funnels, and scorecards, to support business decisions.</li><li>Produce actionable reports that show key performance indicators, identify areas of improvement in current operations, and display root cause analysis of digital performance or experience issues.</li><li>Use analytics and metrics to improve processes and provide data-driven forecasts of potential costs, risks, member impacts, employee impacts, and benefits of new business or digital initiatives.</li><li>Understand data gaps and connect data components across systems to support reliable reporting, visualization, and digital product performance measurement.</li><li>Provide reporting solutions and respond to ad-hoc report requests across Digital and partner business areas, including Product, Marketing, Contact Center Operations, IT, Member Service Operations, and Risk partners as appropriate.</li><li>Create specifications for reports, analysis, dashboards, and measurement plans based on business needs, product objectives, digital release plans, and required or available data elements.</li><li>Assist with the development and enhancement of practices, procedures, data definitions, measurement standards, and documentation that improve consistency across Digital reporting.</li><li>Develop and maintain strong working relationships with team members, subject matter experts, product owners, journey owners, and leaders; work with senior management on complex issues as needed.</li><li>Lead small to medium projects and support larger initiatives that improve Digital BI capabilities, strengthen performance management, or advance digital experience measurement.</li><li>Provide guidance to lower level staff on analytic methods, dashboard design, stakeholder communication, and root cause analysis.</li><li>Manage a portfolio of dashboards and analytic products, monitor usage and performance, and make recommendations to management for enhancements, retirements, or governance changes.</li></ul> Requirements <ul><li>5+ years of experience in data analysis, business intelligence, reporting, or digital analytics.</li><li>Advanced skill using business intelligence applications and/or cloud services to develop reporting, dashboards, and analytic solutions.</li><li>Advanced knowledge of reporting capabilities from enterprise data platforms, ERP, CRM, digital analytics, product analytics, or database software vendors.</li><li>Advanced skill using statistical methods, mathematical techniques, forecasting, cost-benefit analysis, experiment measurement, and root cause analysis.</li><li>Advanced skill with data analysis tools and programming languages such as Python, R, SQL, or comparable analytic tools.</li><li>Advanced knowledge of reporting and dashboarding best practices, data storytelling, data visualization, data research, and root cause analysis techniques.</li><li>Strong stakeholder management skills, with demonstrated ability to influence business partners and translate complex analysis into clear recommendations.</li><li>Advanced knowledge of data integration, data quality, cleaning, validation, metadata, and measurement governance techniques.</li><li>Advanced research skills, including the ability to complete data research, business research, reporting and dashboarding best practices research, needs assessments, and digital performance analysis.</li><li>Strong interpersonal, facilitation, and communication skills, with the ability to collaborate across technical and non-technical audiences.</li></ul><p>System One, and its subsidiaries including Joulé and Mountain Ltd., are leaders in delivering outsourced services and workforce solutions across North America. We help clients get work done more efficiently and economically, without compromising quality. System One not only serves as a valued partner for our clients, but we offer eligible employees health and welfare benefits coverage options including medical, dental, vision, spending accounts, life insurance, voluntary plans, as well as participation in a 401(k) plan.</p><p>System One is an Equal Opportunity Employer. All qualified applicants will receive consideration for employment without regard to race, color, religion, sex (including pregnancy, childbirth, or related medical conditions), sexual orientation, gender identity, age, national origin, disability, family care or medical leave status, genetic information, veteran status, marital status, or any other characteristic protected by applicable federal, state, or local law.</p><p>#M-<b> #LI-<b> Ref: #851-Rockville-S1</b></b></p><p><b></b></p></div></div>

<h3>Job Description</h3><div>Job Description<div><strong>Risk Business Analyst<b> Location: Vienna, VA (Hybrid) <b> Pay Rate: Open to Both C2C and W2 options <b> Position Type: Contract</b></b></b></strong><b> <b> The Analyst will serve in an Asset Based Testing role that will help plan, scope, execute, and report testing of IT and Information Security controls. The Analyst will be responsible for all phases of the assessment and communications with business partners and other stakeholders. They will work in an Agile environment.<b> <b> <strong>Responsibilities:</strong><b> • Planning & Scoping of Asset Based Assessments to include development of communications, risk & control matrices, scope documents and other supporting information<b> • Perform walk-throughs with business partners identifying actual versus expected controls<b> • Create test strategies to test actual controls<b> • Document all work performed to meet the IIA reperformance standard<b> • Document issues and final reports<b> • Present to leadership results of assessments<b> • Any other duties as assigned to support the program<b> <b> <strong>Qualifications:</strong><b> • Experience in control testing to include experience in some of the three lines of defense (Audit, ERM, First Line areas)<b> • Experience in audit and information security risk assessments<b> • Knowledge of applicable federal and state laws, rules and regulations (i.e. Federal Financial Institutions Examination Manual (FFIEC), National Information of Standards and Technology (NIST), and International Standards Organization (ISO)<b> • Knowledge of NCUA, FFIEC, GLBA, NIST (including the Cyber Security Framework and 800 Series), ISO 27001/27002, SANS/CIS 20, PCI DSS, and other Information Security requirements and frameworks<b> • Experience in working with all levels of staff, management, stakeholders, and third parties<b> • Effective planning and organizational skills<b> • Effective research, analytical and problem solving skills<b> • Strong verbal, written and interpersonal communication skills, including technical writing<b> • Bachelor Degree in business, information systems or related field or equivalent work/military experience<b> • CISSP, CISA, CCSP, CRISC or other Information Security certifications<b> • Ability to present findings and conclusions clearly and concisely<b> • Experience in working with all levels of staff, management, stakeholders, and third parties<b> • Ability to build effective relationships through rapport, trust, diplomacy, and tact <b> <b>Ref: #851-Rockville-S1<p><b></b></p></b></b></b></b></b></b></b></b></b></b></b></b></b></b></b></b></b></b></b></b></b></b></b></b></b></b></b></b></div></div>

<h3>Job Description</h3><div>Job Description<div><p><strong>Senior IT Data Engineer<b> Washington, DC – onsite<b> US citizenship required per government contact <b> Must be able to obtain Public Trust clearance<b> Type: Multi-Year Contract supporting Federal Reserve Board<b> Open to W2 and C2C<b> Must apply by 12pm on July 2nd </b></b></b></b></b></b></strong><b> <b> The Data Architecture, Technology, and Analytics (DATA) section is tasked with transforming how the Federal Reserve Board’s Division of Research & Statistics (R&S) ingests, organize, uses, and visualizes data.<b> The Data Architecture, Technology, and Analytics (DATA) section is looking for an experienced detailed oriented Data Architect/Engineer who will be responsible for expanding and optimizing our data and data pipeline architecture, as well as optimizing data flow and collection for economic policy and research teams. The ideal candidate is an experienced hands-on data modeler with working knowledge of database design and administration, data pipeline building, and data wrangling who enjoys improving existing data systems and/or building them from the ground up. The Data Architect/Engineer will support our economists and technical experts and will ensure optimal data delivery architecture is designed and developed. They must have a service mindset, be self-directed, and be comfortable supporting the data needs of multiple teams and systems. The right candidate will be excited by the prospect of optimizing or even re-designing the R&S division’s data architecture to support our next generation of data initiatives.<b> <b> <strong>Technical Skills:</strong><b> • Bachelor’s degree in computer science, Information Technology, Engineering or a related technical field and at least 7 years of related experience; advanced degree preferred.<b> • Advanced working knowledge of SQL and experience working with relational database platforms including PostgreSQL, Microsoft SQL Server, and MySQL.<b> • Advanced working knowledge of Python, R, and other scripting languages used for data engineering and analytics.<b> • Experience working with large-scale data systems, including distributed computing, scalable data processing, data storage architecture, and optimization of high-volume data workloads.<b> • Experience designing, developing, and automating ETL/ELT workflows and data integration pipelines.<b> • Experience building, optimizing, and maintaining scalable databases, data pipelines and data processing frameworks.<b> • Experience with workflow orchestration and pipeline automation tools such as Apache Airflow, Prefect, Dagster, or AWS Step Functions.<b> • Experience migrating workflows and data pipelines between on-premises and cloud environments.<b> • Experience processing, analyzing, and integrating structured and unstructured data sources.<b> • Experience developing in Linux environments and using source control platforms such as GitLab and/or GitHub.<b> • Experience performing root cause analysis on internal and external data and business processes to answer business questions and identify opportunities for improvement.<b> • Ability to design and communicate enterprise information architecture at conceptual, logical, and physical levels.<b> • In-depth experience designing and implementing database, data lake, and enterprise data platform solutions.<b> • Strong hands-on software engineering and implementation experience, including development, testing, and deployment of data applications and services.<b> • Excellent oral and written communication skills with a strong customer service orientation.<b> • Exceptional analytical, problem-solving, and troubleshooting skills.<b> • Understanding of time series data and related analytical and forecasting techniques.<b> • Experience working in a research environment and/or with economic or financial data.<b> • Experience with NoSQL and graph database technologies.<b> • Experience developing, training, deploying, and maintaining machine learning models.<b> • Working experience with cloud technologies such as AWS, Microsoft Azure, and Snowflake.<b> • Experience implementing data warehouses utilizing Change Data Capture (CDC) methodologies.<b> • Experience implementing and maintaining CI/CD pipelines and DataOps platforms.<b> • Working knowledge of additional programming and scripting languages such as Java, Scala, JavaScript, or Perl.<b> <b> </b></b></b></b></b></b></b></b></b></b></b></b></b></b></b></b></b></b></b></b></b></b></b></b></b></b></b></b></b></b></b></p><p>System One, and its subsidiaries including Joulé and Mountain Ltd., are leaders in delivering outsourced services and workforce solutions across North America. We help clients get work done more efficiently and economically, without compromising quality. System One not only serves as a valued partner for our clients, but we offer eligible employees health and welfare benefits coverage options including medical, dental, vision, spending accounts, life insurance, voluntary plans, as well as participation in a 401(k) plan.</p><p>System One is an Equal Opportunity Employer. All qualified applicants will receive consideration for employment without regard to race, color, religion, sex (including pregnancy, childbirth, or related medical conditions), sexual orientation, gender identity, age, national origin, disability, family care or medical leave status, genetic information, veteran status, marital status, or any other characteristic protected by applicable federal, state, or local law.</p><p>#M1<b> #LI-VH1<b> Ref: #851-Rockville-S1</b></b></p><p><b></b></p></div></div>

Calculate Moving Average	SQL	Easy
Predict Customer Churn	Machine Learning	Medium
A/B Test Significance	Statistics	Medium
Optimize Query Performance	SQL	Hard
Feature Importance Analysis	Machine Learning	Medium
Clean Missing Data	Python	Easy
Neural Network Architecture	Deep Learning	Hard
Calculate Cohort Retention	SQL	Medium
Bayesian Probability	Statistics	Easy
Recommend Similar Products	Machine Learning	Hard

System One Interview Questions

System One Interview Guides

System One Interview Questions

Challenge

System One Opening Jobs

Discussion & Interview Experiences

Discussion & Interview Experiences