Table of contents
Home > Interview questions > 20 Common Data Science Interview Questions

20 Common Data Science Interview Questions

People deciding how to answer data science interview questions

Forage puts students first. Our blog articles are written independently by our editorial team. They have not been paid for or sponsored by our partners. See our full editorial guidelines.

If you’re looking for a job in data science, preparing for data science interview questions is, in some respects, no different than preparing for an interview in any other industry. You’ll research the company, practice answers to common interview questions, and review your portfolio to use during the interview.

Data science interview questions also ask about your technical abilities. And while you might be comfortable talking about your abilities, can you explain them in a way that makes sense to the hiring manager?

Preparing for Data Science Interview Questions

It’s not uncommon for a data scientist applicant to go through three to five interviews for the role. This can include a phone interview, Zoom interview, in-person interview, and panel interview

As you might expect, many of the interview questions focus on your hard skills. However, there will also be questions about your soft skills, as well as behavioral interview questions that assess both your hard and soft skills.

BCG logo on building

Data Science

Experience what it's like to be a data scientist in this free course from BCG. Solve problems and answer questions for your "client" by building a model and testing your theory.

Avg. Time: 6-7 hours

Skills you’ll build: Data visualization, hypothesis framing, mathematical modeling, model evaluation, programming, exploratory data analysis

Here’s how to prepare for your data science interview questions.

Go Back to Basics

Start by brushing up on the fundamentals of data science. Review:

  • Statistical analysis: collecting and analyzing large datasets to identify and uncover trends or cause and effect
  • Data hygiene: cleaning and formatting raw data to ensure it’s accurate
  • Coding: writing instructions in “computer speak.”
  • Programming: creating the software or system that executes the coding
  • Data modeling and visualization: presenting data visually to help establish the relationship between data points

Jenna Bellassai, lead data reporter at Forage and former data scientist at Guru, advises applicants to “review fundamental programming and machine learning concepts. Be prepared to describe your contributions to previous projects.”

>>Build practical data skills: The Best Data Job Simulations on Forage to Jumpstart Your Career

Bellassai also advises to “think about what the company’s data may look like, what technical challenges they may face, and where machine learning models could play a role in their business. If you have experience with a niche technology or modeling approach that the company uses, be prepared to speak about it.”

Working at Cognizant

Artificial Intelligence

Home your data science skills in this free course from Cognizant. Gain practical experience working with and training an AI to help your "client" answer questions and make decisions.

Avg. Time: 3-4 hours

Skills you’ll build: Data analysis, Python, data modeling, data visualization, machine learning, quality assurance, model interpretation.

Review Possible Interview Topics

Most interviews include questions about the specifics of the role, and data science interview questions are no different. Bellassai says you can expect technical questions on these topics:

  • Software engineering
  • Data manipulation
  • Statistical modeling (including machine learning topics)
  • Architecture design
  • Distributed computing
  • Cloud architectures
  • Working with specific types of data, like geospatial data

Bellassai also notes that during the interview, you may have to solve a coding problem or draw an architecture diagram.

Data Visualisation

Step into the shoes of a data scientist in this free course from Tata. Learn how to anticipate the questions company leaders will ask and understand which visualizations are best for each situation.

Avg. Time: 3-4 hours

Skills you’ll build: Data analysis, data visualization, data clean-up, analytics, charts and graphs

10 Most Common Data Science Interview Questions

Here are 10 data science interview questions you’ll likely encounter:

  1. What is the difference between supervised and unsupervised learning?
  2. What is the difference between data science and data analytics?
  3. Explain the steps in making a decision tree. How would you create a decision tree?
  4. You’re given a data set that’s missing more than 30% of the values. How do you deal with that?
  5. How do you/should you maintain a deployed model?
  6. How is data science different from other forms of programming?
  7. How often do you/should you update algorithms?
  8. What is the goal of A/B testing?
  9. What are the differences between overfitting and underfitting, and how do you combat them?
  10. What do you prefer using for text analysis?

Bellassai also notes that while you should give your best answer to the question, there is no “right” answer. “Remember that there is no perfect solution. A particular approach isn’t necessarily the best just because you’ve used it before.”

Bonus Round: 10 Common Data Scientist Behavioral Interview Questions

Technical skills aren’t the only kind of data science interview questions you’ll encounter. Like any interview, you’ll likely be asked behavioral questions. These questions help the hiring manager understand how you’ll use your skills on the job.

While your answers will be specific to the role, use the STAR Method to tell a story about a time you put your skills to work and what the outcome was.

Data Science

Improve your data science abilities in this free course from British Airways. Learn how to scrape data then use that information to predict customer behavior.

Avg. Time: 3-4 hours

Skills you’ll build: Web scraping, data manipulation, Python, machine learning, data science, data visulization

Here are 10 data scientist behavioral interview questions: 

  1. Tell me about a time you used data to bring about change at a job.
  2. Have you ever had to explain the technical details of a project to a nontechnical person? How did you do it?
  3. What are your hobbies and interests outside of data science?
  4. Tell me about a time when you worked on a long-term data project. How did you approach collecting and analyzing data when different parts of the project had different deadlines?
  5. How do you align data projects with company goals?
  6. Tell me about a project that didn’t go as planned. How did you manage and overcome the obstacles you encountered?
  7. Do you contribute to open-source projects?
  8. Walk me through a project you’re currently (or recently) working on.
  9. Looking back on a project, what would you do differently to improve it?
  10. How do you go about deciding what should and should not be measured? What happens if members of the team disagree with your opinions?

Get Prepped and Ready

These 20 common data science interview questions should help you get prepped and ready for your next interview. But if you’d like more interview practice, consider enrolling in a free virtual job simulation that focuses on career and interview skills. Learn how to write a killer resume, translate your skills into outcomes, and so much more.

Image Credit: Canva

Rachel Pelta is the Head Writer at Forage. Previously, she was a Content Specialist at FlexJobs, writing articles for job seekers and employers. Her work has been featured in Fast Company, The Ladders, MSN, and Money Talks News.

Get noticed by top recruiters

Learn more