Duo Security, now part of Cisco, is a frontrunner in providing trusted access to secure your organization by leveraging multi-factor authentication and detailed access policies. Founded in 2010, Duo Security has established itself as a leader in the cybersecurity space, offering solutions that protect organizations from breaches and data theft.

As a Data Scientist at Duo Security, you'll be diving into a role that requires a perfect blend of analytical skills, creativity, and business acumen. Your primary responsibilities will involve leveraging statistical analysis, machine learning models, and data-driven insights to enhance the security framework. This position demands a robust understanding of data manipulation, predictive modeling, and cybersecurity dynamics.

With this guide from Interview Query, we aim to demystify the interview process at Duo Security, walking you through the key aspects of the role, typical interview stages, and sample questions. Let’s prepare you for an exciting journey ahead!

Submitting Your Application

The first step is to submit a compelling application that reflects your technical skills and interest in joining Duo Security as a data scientist. Whether you were contacted by a Duo Security recruiter or have taken the initiative yourself, carefully review the job description and tailor your CV according to the prerequisites.

Tailoring your CV may include identifying specific keywords that the hiring manager might use to filter resumes and crafting a targeted cover letter. Furthermore, don’t forget to highlight relevant skills and mention your work experiences.

Recruiter/Hiring Manager Call Screening

If your CV happens to be among the shortlisted few, a recruiter from the Duo Security Talent Acquisition Team will make contact and verify key details like your experiences and skill level. Behavioral questions may also be a part of the screening process.

In some cases, the Duo Security data scientist hiring manager stays present during the screening round to answer your queries about the role and the company itself. They may also indulge in surface-level technical and behavioral discussions.

The whole recruiter call should take about 30 minutes.

Technical Virtual Interview

Successfully navigating the recruiter round will present you with an invitation for the technical screening round. Technical screening for the Duo Security data scientist role usually is conducted through virtual means, including video conference and screen sharing. Questions in this 1-hour long interview stage may revolve around Duo Security’s data systems, ETL pipelines, and SQL queries.

In the case of data scientist roles, take-home assignments regarding product metrics, analytics, and data visualization are incorporated. Apart from these, your proficiency against hypothesis testing, probability distributions, and machine learning fundamentals may also be assessed during the round.

Depending on the seniority of the position, case studies and similar real-scenario problems may also be assigned.

Onsite Interview Rounds

Followed by a second recruiter call outlining the next stage, you’ll be invited to attend the onsite interview loop. Multiple interview rounds, varying with the role, will be conducted during your day at the Duo Security office. Your technical prowess, including programming and ML modeling capabilities, will be evaluated against the finalized candidates throughout these interviews.

If you were assigned take-home exercises, a presentation round may also await you during the onsite interview for the data scientist role at Duo Security.

Quick Tips For Duo Security Data Scientist Interviews

• Should contain three tips for interviewing for this specific company based on interview experiences.

Example:

You should plan to brush up on any technical skills and try as many practice interview questions and mock interviews as possible. A few tips for acing your Duo Security interview include:

• Understand Duo Security’s Products: Duo Security questions are standardized and rely heavily on situational scenarios with their products. Study Duo Security’s large breadth of products and understand how you would personally improve or test them.
• Be Data Driven: Duo Security’s data science interviews assess how well you can provide business-driving insights with data science. Brush up on your knowledge of statistics and probability, given these questions can be some of the hardest to solve.
• Embody the Spirit: Duo Security at its core has a collaborative, employee-focused culture that values innovation. Practice responding to behavioral questions with answers that touch on Duo Security’s core values.

Typically, interviews at Duo Security vary by role and team, but commonly Data Scientist interviews follow a fairly standardized process across these question topics.

• Create a function is_subsequence to determine if one string is a subsequence of another. Given two strings, string1 and string2, write a function is_subsequence to find out if string1 is a subsequence of string2.

• Implement a SinglyLinkedList class with methods to manipulate the list. Create a class SinglyLinkedList with methods to add and remove elements from the head and tail, check for item existence, access elements by index, and get the list's length.

• Write a function swap_node to swap nodes at given positions in a singly linked list. Given the head of a singly linked list and two positions x and y, write a function swap_node to swap the nodes at these positions using pointer manipulation, not by swapping values.

• Would a logistic model still be valid if a key variable had data quality issues? Assume a logistic model is heavily weighted on one variable, and there was a data quality issue where some values lost their decimal points (e.g., 100.00 turned into 10000). Would the model still be valid? Why or why not? How would you fix the model?

• How would you design a system to minimize missing or wrong orders on DoorDash? As a data scientist at DoorDash, you need to build a machine learning system to minimize missing or wrong orders placed on the app. How would you go about designing this system?

• What is the relationship between PCA and K-means clustering? Explain the relationship between Principal Component Analysis (PCA) and K-means clustering.

• How would you classify posts by topic on a large-scale social media website? You work at a social media website and need to build a system to automatically detect the topic of new posts, given that several thousand posts are created every hour. How would you create a machine learning model to classify posts by topic given the scale of the data?

• What are kernel methods in machine learning, and what are the requirements for a matrix to represent a kernel?

• What are kernel methods in machine learning?
• What are the requirements for a matrix to represent a kernel?
• What happens if we run a support vector machine model using a kernel that does not satisfy these requirements?

Landing a Data Scientist position at Duo Security is a thrilling opportunity to leverage your analytics and machine learning skills in a cutting-edge cybersecurity environment. From initial phone screens to rigorous technical assessments, and finally, behavioral interviews, Duo Security ensures they are bringing top-tier talent on board. If you want more insights about the company, check out our main Duo Security Interview Guide, where we have covered many interview questions that could be asked. We’ve also created interview guides for other roles, such as software engineer and data analyst, where you can learn more about Duo Security’s interview process for different positions.

At Interview Query, we empower you to unlock your interview prowess with a comprehensive toolkit, equipping you with the knowledge, confidence, and strategic guidance to conquer every Duo Security interview question and challenge.

You can check out all our company interview guides for better preparation, and if you have any questions, don’t hesitate to reach out to us.

Good luck with your interview!