Deloitte Data Scientist Interview Questions + Guide in 2024

With a worldwide workforce of over 450,000 driving operations, Deloitte offers law and accounting services, providing audit, consulting, tax, and legal consultation. However, software development, cloud solutions, and data analytics correspondingly contribute to Deloitte’s massive success.

As a primarily financial firm, Deloitte highly values data scientists, raising the stakes of the interview further. Deloitte data scientists generally perform risk analyses and reliability assessments. They also deploy analytical and machine learning models into production.

Likely, you’re here to gain insights into the interview process for the data scientist role at Deloitte and brush up on the topics typically covered in the questions.

So, let’s get to it.

Irrespective of the job role, candidates often reflect on the sheer number of rounds and intensity of the Deloitte interviews. As a data scientist candidate, expect in-depth behavioral and technical questions about your experience, real-world problems, and case studies.

Here’s some inside information regarding the Deloitte data scientist interview:

Submitting Online Application

Depending on your creds and industry experience, a Talent Acquisition team member might reach out and encourage you to apply for the open data scientist roles at Deloitte. If not, stay tuned to the Deloitte Career portal to apply for the data scientist roles that interest you.

Be sure to submit an updated CV clearly outlining relevant skills and experiences. Moreover, peruse the job description to learn the key selection criteria and tailor your application accordingly.

Initial Screening Process

If your CV has been shortlisted, a member of the Deloitte Talent Acquisition team will contact you for a telephone screening. Your skills and experiences will be matched against the key job requirements to determine your cultural and technical suitability.

During this round, you will be asked a few behavioral questions and a few pre-defined questions about your experience and skills. If your contact at Talent Acquisition is satisfied with your answers, you will advance to the technical rounds.

Telephone Technical Interview

The first technical round usually comprises a telephone screening interview. It’s usually conducted by a member of the Deloitte data scientist team on basic algorithm and machine learning concepts. This is also your opportunity to learn more about the role and Deloitte itself. Multiple interviewers may be present to evaluate your skills.

Face-to-Face Technical Interview

Typically, a panel of interviewers, including your hiring manager, will be present to conduct the face-to-face technical interview round. Strive to demonstrate your in-depth knowledge regarding different aspects of data science, machine learning, and algorithms.

Recently, Generative AI solutions, AI tools, ML models, and large-scale data ecosystems have dominated the data scientist interview questionnaire at Deloitte.

If successful, a partner or director will schedule a meeting to ask a few behavioral questions and congratulate you.

Offer and Onboarding

You will receive both verbal and written confirmation of your success at the Deloitte data scientist interview. After a series of pre-employment checks and psychometric tests (if applicable), you’ll be onboarded and trained to do your job effectively.

As a data scientist at Deloitte, you’re expected to understand statistics, machine learning concepts, and programming languages. You also are expected to be an efficient communicator and team player. To validate your credentials, your Deloitte interviewers will ask you several behavioral and technical questions regarding the topics. Some of these are discussed below:

1. What are your three greatest strengths and weaknesses?

A Deloitte interviewer may ask this question to understand how you perceive your strengths and weaknesses and how you handle self-assessment.

How to Answer

Highlight strengths like problem-solving skills, adaptability, and collaboration. Be honest about weaknesses but also demonstrate self-awareness and a willingness to improve. Frame weaknesses as areas for growth and development.

Example

“My problem-solving skills are strong, as I often find creative solutions to complex problems. Additionally, my adaptability allows me to quickly adjust to new situations. Regarding weaknesses, sometimes I struggle with time management, but I’m improving my organization and prioritization skills through tools like time-blocking and task lists.”

2. How do you prioritize and stay organized when you have multiple deadlines?

This question will assess your ability to manage time effectively and stay organized in a fast-paced environment, which is crucial for success in data scientist roles.

How to Answer

Discuss your method for prioritizing tasks based on urgency, importance, and impact. Mention strategies like creating a timeline, breaking tasks into smaller steps, and communicating with stakeholders to manage expectations.

Example

“When faced with multiple deadlines, I first assess the urgency and importance of each task. I create a timeline outlining key milestones and allot time for each task accordingly. Breaking down tasks into smaller, manageable steps helps me stay focused and organized. Additionally, I communicate with stakeholders to ensure our priorities align and to manage expectations regarding deliverables.”

3. Describe a situation where you had to work effectively under pressure. What was the outcome?

This question evaluates your ability to perform well in stressful situations. This is essential to working at Deloitte, where tight deadlines and high-pressure environments are common.

How to Answer

Describe a situation where you faced pressure, explain how you managed it, and highlight the positive outcome. Emphasize your ability to stay focused, make decisions under pressure, and maintain a positive attitude.

Example

“In a previous role, we encountered a critical issue just before a major project deadline. Despite the pressure, I remained calm and focused on finding a solution. I quickly assessed the situation, delegated tasks to team members, and communicated effectively with stakeholders. Our teamwork and efficient problem-solving paid off, as we successfully resolved the issue and met the deadline.”

4. Tell me about a time you explained a complex idea to someone with little background knowledge. How did you ensure they understood?

Deloitte may ask this question to evaluate your clarity, patience, and adaptability in explaining complex ideas to non-technical audiences, such as directors and clients.

How to Answer

Reflect on an instance where you had to explain a complex idea to someone with limited background knowledge. Highlight your ability to simplify complex concepts, use analogies or visuals, and actively engage the listener to ensure comprehension.

Example

“In a previous project, I had to explain a complex statistical model to a client without a background in data science. To ensure they understood, I used relatable analogies and visual aids to illustrate key concepts. I also encouraged questions and feedback to ensure they understood and addressed misconceptions. By tailoring my communication approach to the audience’s level of understanding, I successfully explained the complex idea in a way that was accessible and meaningful to them.”

5. Tell me about a time you disagreed with a teammate’s approach to a project. How did you resolve the disagreement?

This question will assess your conflict resolution skills and ability to work in a team environment as a data scientist at Deloitte, where teamwork and collaboration are paramount.

How to Answer

Explain a disagreement with a teammate and how you addressed it, emphasizing the positive outcome. Highlight your ability to listen actively, seek common ground, and find mutually beneficial solutions through open communication and compromise.

Example

“In a recent project, my teammate and I had differing opinions on approaching a problem. Instead of letting the disagreement escalate, I initiated a constructive conversation to understand their perspective and share my own. We actively listened to each other’s concerns, identified common goals, and brainstormed alternative solutions. Through open communication and compromise, we reached an agreement that combined the strengths of both approaches. As a result, we were able to move forward with a unified strategy and succeed in the project.”

6. Suppose you work for an artificial intelligence team at ABC Neural Inc.

Your team’s task is to create a product that predicts the number of daily transit riders of the New York City Subway at a given hour. You’ll receive hourly data supplied from your client’s database to use as training data to supplement your current AI working dataset. Predictions should be delivered on an hourly basis. To start your project, what are the product’s requirements?

The Deloitte data scientist interviewer will seek to assess your ability to outline the essential requirements for a predictive model to forecast the number of daily transit riders for the New York City Subway.

How to Answer

To answer this question, consider critical aspects such as data sources, prediction frequency, performance metrics, model interpretability, scalability, and deployment constraints. Use the information to reflect on how you would approach building the product.

Example

“A predictive model for NYC Subway ridership should use hourly data and provide forecasts on an hourly basis. Data sources include historical transit data, weather conditions, special events, and public holidays. Performance metrics should include accuracy, precision, and recall. The model must be interpretable for stakeholders and scalable to handle increasing data volumes. Deployment should be seamless within existing infrastructure.”

7. Given a list of integers, identify all the duplicate values. Assume that the list can contain both positive and negative numbers, and the order of the list does not matter. A number is considered a duplicate if it appears more than once in the list. Return a list of the duplicate numbers.

Example 1:

Input:

nums = [1, 2, 3, 1, 2, 3]

Output:

find_duplicates(nums) -> [1, 2, 3]

The numbers 1, 2, and 3 all appear more than once in the list, so they are considered duplicates.

Example 2:

Input:

nums = [1, -1, 2, 3, 3, -1]

Output:

find_duplicates(nums) -> [-1, 3]

The numbers -1 and 3 appear more than once in the list, so they are considered duplicates. The order of the output does not matter.

Example 3:

Input:

nums = [1, 2, 3, 4, 5]

Output:

find_duplicates(nums) -> []

None of the numbers in the list appear more than once, so there are no duplicates.

Deloitte may ask this question to gauge your understanding of basic data manipulation techniques and algorithmic problem-solving skills as a data scientist.

How to Answer

Iterate through the list, maintaining a dictionary to store each number’s count. Then, return numbers with counts greater than one.

Example

def find_duplicates(nums):
    counts = {}
    duplicates = []
    for num in nums:
        if num in counts:
            counts[num] += 1
        else:
            counts[num] = 1
    for num, count in counts.items():
        if count > 1:
            duplicates.append(num)
    return duplicates

8. You are given two lists of strings, list1 and list2, which are sorted alphabetically in ascending order. Implement a function that merges these two lists into one sorted list, marking all items from list1 and list2 with characters "1" and "2" respectively at the end of each item, and return that list.

Example:

Input:

list1 = ["ball","ninja","plan"]
list2 = ["cat","egg","zoo"]

Output:

def mark_lists(list1,list2) ->
["ball1","cat2","egg2","ninja1","plan1","zoo2"]

This question tests your ability to merge and mark items from two sorted lists into a single sorted list.

How to Answer

Merge the lists while iterating through them simultaneously and mark each item with the respective list number.

Example

def mark_lists(list1, list2):
    first_index = 0
    second_index = 0

    result = []

    while first_index < len(list1) and second_index < len(list2):
        if list1[first_index] <= list2[second_index]:
            result.append(list1[first_index]+'1')
            first_index += 1
        else:
            result.append(list2[second_index]+'2')
            second_index += 1

    while first_index < len(list1):
        result.append(list1[first_index]+'1')
        first_index += 1

    while second_index < len(list2):
        result.append(list2[second_index]+'2')
        second_index += 1

    return result

9. Let’s say that you’re working on a job recommendation engine. You have access to all user LinkedIn profiles, a list of jobs each user applied to, and answers to questions that the user filled in about their job search. Using this information, how would you build a job recommendation feed?

The interviewer representing Deloitte for the data scientist role may ask this question to evaluate your understanding of recommendation algorithms and data integration.

How to Answer

Mention how you would use user profiles, job applications, and responses to construct user-job similarity metrics. Explain that you might employ collaborative filtering or content-based filtering techniques and leverage machine learning algorithms for personalized recommendations.

Example

“To build a job recommendation engine, I would start by creating user-job similarity matrices based on user profiles, job applications, and user responses. Then, I’d apply collaborative filtering techniques to recommend jobs similar to those applied for by similar users. Additionally, I’d use content-based filtering to recommend jobs based on user preferences and job characteristics. Finally, I’d incorporate machine learning models to personalize recommendations further.”

10. Imagine you are asked to build a machine learning model to decide on new loan approvals for a financial firm.

You ask the data department in the company for a subset of data to get started working on the problem. The data includes different features about applicants, such as age, occupation, zip code, height, number of children, favorite color, etc. You decide to build multiple machine learning models to test out different ideas before settling on the best one. How would you explain the bias-variance tradeoff with regard to building and choosing a model to use?

This question evaluates your understanding of the bias-variance tradeoff in the context of building machine-learning models for loan approvals.

How to Answer

Explain how models with high bias tend to oversimplify relationships, leading to underfitting, while models with high variance capture noise, leading to overfitting. Emphasize the importance of finding the right balance between bias and variance to achieve optimal model performance.

Example

“The bias-variance tradeoff refers to the tradeoff between model simplicity and flexibility. Models with high bias, such as linear regression, oversimplify relationships and may fail to capture complex patterns, resulting in underfitting. On the other hand, models with high variance, such as decision trees, capture noise in the training data and may perform well on training data but poorly on unseen data, leading to overfitting. The goal is to find the optimal balance between bias and variance to achieve the best generalization performance on unseen data.”

11. Write a query that retrieves the percentage of users who recommended each page and are located in the same postal code as that page.

Note: A page can sponsor multiple postal codes.

Example:

Input:

page_sponsorships table

Column	Type
page_id	INTEGER
postal_code	VARCHAR
price	FLOAT

recommendations table

Column	Type
user_id	INTEGER
page_id	INTEGER

users table

Column	Type
id	INTEGER
postal_code	VARCHAR

Output:

Column	Type
page	INTEGER
postal_code	VARCHAR
percentage	FLOAT

Your Deloitte data scientist interviewer may ask this question to evaluate your proficiency in data manipulation and aggregation, as well as your understanding of relational database concepts.

How to Answer

Begin by joining the page_sponsorships, recommendations, and users tables using appropriate join conditions. Then, group by page_id and postal_code, and calculate the percentage of users who recommended the page and are in the same postal code. Use SQL functions such as COUNT() and SUM() to perform the necessary calculations.

Example

SELECT s.page_id AS page,
  s.postal_code,
  COUNT(CASE WHEN s.postal_code = u.postal_code THEN r.user_id ELSE null END)/COUNT(r.user_id) as percentage
FROM page_sponsorships s
JOIN recommendations r
ON s.page_id = r.page_id
JOIN users u
ON r.user_id = u.id
GROUP BY 1,2

12. Suppose we have a binary classification model that classifies whether or not an applicant should be qualified to get a loan. Because we are a financial company, we must provide each rejected applicant with a reason for their rejection. Given that we lack access to feature weights, how would we fulfill this requirement?

The interviewer may use this question for the data scientist role to assess your problem-solving skills and understanding of model interpretability.

How to Answer

Propose methods for providing reasons for rejection without relying on feature weights. Consider techniques such as using model-agnostic interpretability methods like SHAP values, decision trees, or rule-based systems to identify key features contributing to rejection decisions.

Example

“One approach to providing rejection reasons without access to feature weights is to use model-agnostic interpretability techniques such as SHAP values. By analyzing the SHAP values for each applicant, we can identify which features contributed the most to the rejection decision and provide those as reasons. Another approach could involve using decision trees or rule-based systems to generate rejection rules based on the applicant’s feature values.”

13. What are time series models? Why do we need them when we have less complicated regression models?

Deloitte may ask this question to gauge your knowledge of specialized modeling techniques required for analyzing time-dependent data and your ability to articulate their advantages over simpler regression models.

How to Answer

Explain the concept of time series models, emphasizing their ability to capture temporal dependencies and patterns in sequential data. Highlight scenarios where time series models outperform regression models.

Example

“Time series models are statistical models designed to analyze data points collected over time. Unlike regression models, which focus on relationships between independent and dependent variables, time series models consider the temporal order of observations. They are essential when analyzing data with inherent sequential dependencies, such as stock prices, weather patterns, or economic indicators. Time series models can capture seasonality, trends, and irregularities in data, making them particularly suitable for forecasting future values or identifying patterns over time.”

14. A client wants a high-level overview of their sales data by region. How would you break down the data and present the findings clearly and concisely?

The interviewer at Deloitte may ask this question to assess your communication skills as a data scientist and your understanding of data visualization and storytelling techniques.

How to Answer

Discuss how you would approach breaking down sales data by region. Emphasize the importance of tailoring the presentation to the client’s needs and preferences.

Example

“To provide a high-level overview of sales data by region, I would first aggregate the data by region, summarizing metrics such as total sales, average sales per customer, and sales growth rate. Then, I would visualize the findings using interactive dashboards or geographical maps to highlight regional sales performance and trends. Additionally, I would incorporate narrative elements to contextualize the data and provide actionable insights for the client.”

15. What evaluation metrics would you use for a binary classification problem?

This question assesses your knowledge of evaluation metrics commonly used in binary classification tasks.

How to Answer

Discuss commonly used evaluation metrics for binary classification. Explain the significance of each metric and discuss scenarios where one metric may be more appropriate than others.

Example

“For a binary classification problem, several evaluation metrics can assess the model’s performance. Accuracy measures the overall correctness of predictions, while precision and recall quantify the trade-off between false positives and false negatives, respectively. The F1 score provides a harmonic mean of precision and recall, balancing between the two metrics. Additionally, ROC-AUC evaluates the model’s ability to distinguish between positive and negative classes across various thresholds. The choice of metric depends on the problem context; for instance, precision and recall may be more informative than accuracy in imbalanced datasets.”

16. You are analyzing a large dataset and notice some outliers. How would you decide whether to keep them or remove them?

Your interviewer for the data scientist role at Deloitte may ask this question to understand your approach to data preprocessing and outlier management, as it directly impacts the accuracy of analytical models.

How to Answer

First, conduct exploratory data analysis (EDA) to understand the nature and potential impact of outliers on the data distribution and analytical goals. Then, consider statistical techniques to identify outliers. Finally, make an informed decision based on the analysis.

Example

“I would start by conducting an exploratory data analysis to visualize the distribution of the data and identify potential outliers. Then, I would apply statistical methods such as calculating z-scores or using the interquartile range (IQR) to detect outliers. However, I wouldn’t automatically remove outliers without considering their impact on the analysis. Instead, I would assess whether the outliers are due to data entry errors, natural variations, or represent genuine anomalies in the data. Depending on the context and objectives of the analysis, I would decide whether to keep, remove, or transform the outliers accordingly.”

17. You are building a model to predict customer churn. What evaluation metrics would you use to measure its performance?

This question evaluates your understanding, as a data scientist, of model evaluation metrics relevant to predicting customer churn.

How to Answer

When building a model to predict customer churn, you would typically consider evaluation metrics. Each metric provides insights into different aspects of model performance. It’s essential to choose metrics that align with business objectives and account for class imbalance in the dataset.

Example

“For predicting customer churn, I would consider several evaluation metrics such as accuracy, precision, recall, F1-score, and ROC-AUC. Accuracy gives an overall measure of correct predictions while precision and recall provide insights into the model’s ability to correctly identify churn cases without missing too many or misclassifying non-churn instances. F1-score balances precision and recall, making it useful for imbalanced datasets. Additionally, ROC-AUC assesses the model’s ability to discriminate between churn and non-churn instances across different probability thresholds. By considering these metrics together, we can gain a comprehensive understanding of the model’s performance and its effectiveness in addressing the business objective of reducing customer churn.”

18. One of our clients wants to improve customer lifetime value (CLTV). How would you use survival analysis or time series forecasting to predict future customer behavior?

Your ability to apply advanced analytical techniques like survival analysis and time series forecasting to solve business problems related to customer lifetime value will be assessed through this question.

How to Answer

To predict future customer behavior and improve CLTV, you can use survival analysis to model the time until customers churn or make repeat purchases. Time series forecasting techniques can also be employed to predict future purchasing patterns and revenue streams based on historical data.

Example

“I would first preprocess the data by aggregating customer transactions and defining the time intervals for analysis. Then, I would apply survival analysis techniques such as Kaplan-Meier estimation or Cox proportional hazards model to model the probability of churn or repeat purchases over time. Additionally, I would use time series forecasting methods like ARIMA or exponential smoothing to predict future customer spending patterns and revenue streams. By combining these approaches, we can gain insights into customer behavior dynamics and identify strategies to enhance CLTV, such as targeted marketing campaigns or personalized retention incentives.”

19. Assume Deloitte is building a recommendation engine for a streaming service. What machine learning algorithms would you explore, and how would you handle cold-start problems (new users/items)?

This question evaluates your knowledge of recommendation systems and your ability to address challenges, such as cold-start problems, when building a recommendation engine.

How to Answer

You could explore collaborative filtering methods like user-based or item-based filtering and matrix factorization techniques. To handle cold-start problems for new users or items, you can use hybrid recommendation systems, incorporating knowledge-based or popularity-based recommendations initially and gradually transitioning to personalized recommendations as more data becomes available.

Example

“I would consider collaborative filtering methods like user-based or item-based approaches, as they leverage user-item interactions to generate recommendations. Additionally, matrix factorization techniques, such as singular value decomposition (SVD) or alternating least squares (ALS), can capture latent factors in the data and provide personalized recommendations. To address cold-start problems for new users or items, I would initially rely on knowledge-based recommendations or popularity-based strategies to provide generic recommendations. As more data accumulates, we can gradually incorporate collaborative or content-based filtering techniques to deliver personalized recommendations tailored to individual preferences.”

20. A client wants to develop a computer vision system to automate product inspection in their manufacturing process. What factors would you consider when choosing a deep learning architecture (e.g., CNN vs RNN) for this task?

The interviewer at Deloitte may ask this question to evaluate your knowledge of convolutional neural networks (CNNs) and recurrent neural networks (RNNs) and your expertise in applying deep learning techniques to solve real-world problems in manufacturing and quality control.

How to Answer

When choosing a deep learning architecture for automated product inspection, consider factors such as the nature of the visual data, spatial vs temporal dependencies in the data, computational efficiency, interpretability of results, and model scalability. Also, mention which factor suits which task.

Example

“I would consider the nature of the visual data and the specific requirements of the product inspection task when choosing between CNNs and RNNs. Since automated product inspection typically involves processing images to detect defects or anomalies, a convolutional neural network (CNN) would be the primary choice due to its effectiveness in capturing spatial features from images. Additionally, if the inspection process involves analyzing sequential data or temporal dependencies, such as detecting defects in a continuous manufacturing process captured in video footage, recurrent neural networks (RNNs) might be more appropriate for capturing temporal patterns and long-range dependencies.”

An actionable understanding of data science concepts and tools is essential to ace the Deloitte data scientist interview. Here’s how you can effectively prepare for the interview:

Understand Deloitte’s Culture

Learn Deloitte’s culture and values to prepare answers to common behavioral questions accordingly. Refine your answers, especially to experience-based questions, to suit the fast-paced and communication-heavy data scientist roles at Deloitte.

Refine Essential Skills and Knowledge Bases

Refine your data science and Python skills to enter the Deloitte data scientist interview with confidence. Also, consider brushing up on common SQL data science questions and machine learning concepts to successfully tackle any “mind-benders” your interviewer may present.

Master Data Science Tools

Deloitte deals with large volumes of data, both structured and unstructured. Familiarity with big data technologies such as Hadoop, Spark, Hive, and Pig can be advantageous for handling and processing massive datasets efficiently. Tools like Tableau, Power BI, or Matplotlib can help create compelling visualizations to present findings to clients and stakeholders.

Familiarize Yourself with Case Studies and Takehomes

Case study interview questions and takehomes often present the real-world scenarios that are typically asked in Deloitte data scientist interviews. These challenges can solidify your data scientist foundation and help you achieve success in the upcoming Deloitte interview.

Prepare with Mock Interviews and Professional Guidance

Mock interviews simulate real interview scenarios, allowing you to experience the pressure and dynamics of an actual interview. Our P2P Mock Interview setup can help you identify your strengths and weaknesses in communication, problem-solving, and technical skills. Our AI-assisted Interview Mentor may also help refine your approach further.

How much do data scientists at Deloitte make in a year?

The average salary for data scientists at Deloitte can vary depending on the specific role. Still, the base compensation averages $112,000, with the total compensation reaching up to $181,000 for experienced data scientists.

Compare Deloitte’s salary with industry-wide data scientist salaries to get a more accurate idea.

Where can I read about other people’s interview experiences for the Deloitte data scientist role?

If you’re interested in learning about other people’s interview experiences for the Deloitte data scientist role, you’re welcome to explore our exponentially growing Slack channel.

You may also submit your own experience with the upcoming batch of data science candidates.

Does Interview Query have job postings for the Deloitte data scientist role?

Yes, we do have an updated job board to showcase the latest job openings, including the Deloitte data scientist role. However, we recommend you continue perusing the official career websites to discover additional opportunities.

Nailing the Deloitte data scientist interview is not easy. We’ve detailed the interview process, answered a few common questions, and shared some practical tips. Our main Deloitte interview guide is there to support you, but no amount of guidance will be enough if you don’t give your best. While at it, consider other Deloitte opportunities, including business analyst, data analyst, machine learning engineer, and software engineer roles.

The IQ team wishes you all the best in your upcoming interview. We’re here to help you in every way possible.