Data Masked
Trusted by 10K+ data scientists since 2015• New GenAI DS case studies

The best resource for data science interviews since 2015

Includes the original "A collection of data science take-home challenges" and product case studies about A/B testing, metrics, and insights

The original since 2015 • Updated in 2026

Real data science

Product Case Studies

Learn how to answer the hardest product, metrics, and A/B testing interview questions, like: Should we add this feature? Which metric should we use?

Data Challenges

Practice in advance on challenges just like the ones you will get in the interview, resembling what you will actually do at work

Coding

Reusable solution frameworks for SQL/Python/R exercises just like what you will get in the on-site or shared-screen interview

“ This material helped me get a Data Scientist job at Facebook ”

Menghan Xu

Samples

NEW

GenAI Data Science Product Case Studies

New case studies for GenAI DS roles. Learn what GenAI data scientists are doing at Google, OpenAI, Meta, and more to launch and optimize AI products

GenAI DS Case Studies->

“ I bought the material and as a result I got a job as a Data Scientist at Pinterest! ”

Dorna Bandari

Products and features

The original

Interview Material

  • ✔ The original DS takehome challenges: 20 take-home challenges with real world data sets. 4 challenges have detailed solutions with reusable step by step code in Python and R
  • ✔ 40 DS product questions with answers. This is a subset of just 40 among all the product questions included in the full course. These 40 questions are introductory and more high-level, while the additional ones in the full course are harder and more applied
  • ✔ 3 sections on coding questions for DS interviews. Learn how to categorize coding questions and apply a reusable framework to each category, removing randomness from the live coding step. Includes SQL, Python, and R solutions to the hardest questions asked at top tech companies
Best seller

Full Course in Product Data Science

  • ✔ Learn how to develop product sense, create metrics, and design robust A/B tests
  • ✔ 12 sections with more than 130 lessons and exercises leveraging real tech company tables (user table, event table, etc.). Code in Python, R, and SQL
  • ✔ Includes everything in the interview material package + R/Python solutions for all the challenges (not just 4) + tons of additional DS Product Questions
  • ✔ Unlimited 1:1 support from author throughout the course. Can ask any questions you have about the material or anything related to product data science
  • ✔ Approved as an employee training expense by >200 companies
New

GenAI Data Science Case Studies

  • ✔ 40 brand new GenAI DS case studies with detailed answers
  • ✔ Focus is on what changed from Product DS to GenAI DS (best for people who already know Product DS concepts)
  • ✔ Based on inside knowledge about real AI projects at a handful of top tech companies (OpenAI, Google, Meta, Amazon, Airbnb, etc.)
  • ✔ Straightforward approval as an employee training expense (same process used at >200 companies for the Product DS course)

“ Excellent resource for interview prep. Highly recommended ”

Donja Darai, Sr. DS at eBay

Course Author

Giulio Palombo

I have been creating educational material related to data science since 2015. Firstly focusing on job interviews (A Collection of Data Science Take-Home Challenges, 40 Data Science Product Questions, DS Coding Course, now all combined into a single package) and, more recently, focusing on employee training.

The Full Course in Product Data Science was among the fastest courses ever to reach $1 million in sales on Teachable. The main idea behind everything is to simulate/recreate the actual work data scientists do inside top tech companies.

Prior to all this, I worked as a data scientist for several Silicon Valley tech companies, the last one being Airbnb.

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