The material helped me so much get a data scientist job at Facebook!Menghan Xu

Has led to offers at:

I bought the material and as a result I got a job as a Data Scientist at Pinterest! Dorna Bandari

Real data science!

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

Product On-Site Questions

Learn how to answer the hardest product, metric, A/B testing on-site questions. Such as: Should we add the love button on FB?, Which metric would you choose for this new feature?, etc.


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

1:1 Coaching

Personalized mentorship from book author on how to tackle data challenges and answer product questions

The phone call to discuss in advance onsite questions was very useful to get a DS job at! Doudou Tang

Take-home challenge samples:

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.

  • ☑ DS product questions with answers: 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

  • NEW 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.

Full course in product data science

  • ☑ Learn how to develop product sense, create metrics, and design robust A/B tests

  • ☑ Includes everything in the interview material package + R/Python solutions for all the challenges (not just 4) + tons of additional DS Product Questions

  • ☑ 12 sections with more than 130 lessons and exercises in total. Code in R, Python, and SQL

  • ☑ Real tech company tables, i.e. user table, event table, A/B test tables, etc.

  • ☑ 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

  • Click below to check out full curriculum, samples, product features, and pricing

AI for Data Scientists

  • ☑ Learn how to build and monetize Chatgpt apps. The course is based on the real-world business experience of having built and subsequently sold a Chatgpt-powered app to a Fortune 500 company (Colgate)

  • ☑ Includes Chatgpt foundational knowledge, real-world projects based on reverse-engineering the code of successful AI products, and step-by-step tutorial on how to build production-ready apps

  • ☑ Only requirement is knowledge of Python or R. No prior AI or Web-Development knowledge required

  • ☑ Unlimited 1:1 support from author throughout the course. Can ask any questions about the course material or anything related to AI as you are building your own project

  • Click below to check out full curriculum, samples, product features, and pricing

All Take-Home Challenges

Beside the challenges, the introduction gives general advice on how to tackle data science take-home challenges. What hiring managers are looking for, how to break down the problem, what you should focus on, etc.

1. Conversion Rate

One of the most common applications of data science: look at users coming to your site, predict who is going to convert and come up with ideas to improve conversion rate!

2. Translation A/B Test

In this challenge, you will check if an A/B test has been successful. Also, you will have to find out why results look counter-intuitive and design an algorithm to avoid that problem in future!

3. Employee Retention

People data science! Can you predict when and why an employee is about to quit? This is one of the most recent, impactful and interesting applications of data science!

4. Fraudulent Activities

Any website transacting money has a team of data scientists, often called "risk team", to predict whether a transaction is fraudulent. Build the model and design a personalized user experience based on the model output.

5. Funnel Analysis

Look at how users use your site, where they click, and optimize user experience! Check click-through-rate for each page of your site and identify: what's broken, guess why and come up with ideas to improve conversion rate!

6. Pricing Test

Optimize pricing on your site by looking at a pricing A/B test results! Can you improve revenue by offering different prices to different kinds of users?

7. Marketing Email Campaign

Use Machine Learning to predict when to send a marketing email and what should be the email characteristics if you want to maximize the campaign effectiveness! Come up with ideas to personalize the email campaign so that different users get different emails!

8. Song Challenge

Very early stage startups work with json files! You'll have to parse a json and build a song recommendation model in order to increase user engagement!

9. Clustering Grocery Items

Look at user online purchases and try to automatically create categories based on what users are buying together!

10. Credit Card Transactions

Anomaly detection! Use unsupervised machine learning to identify credit card transactions that appear suspicious!

11. User Referral Program

Sites offer you a reward if you send an invite to a new user and the new user uses the product. Let's find out with this challenge the impact of a referral program!

12. Loan granting

One of the hottest fintech topics here! We have data here about when a bank grants a loan. Try to beat their model and create a more efficient way to decide who should receive a loan!

13. City Similarities

Look at user browsing behavior on a hotel travel site and cluster them based on the browsing behavior. Can you predict in an unsupervised way who is going to book a hotel?

14. Optimization of Employee Shuttle Stops

Using data to optimize the off-line world! Based on employee home address, optimize the best shuttle stop location!

15. Diversity in the Workplace

Hot topic here! Look at data about employee salaries, title, and experience and figure out if the company is treating its employees fairly or there is some discrimination going on!

16. URL Parsing Challenge

Learn how to parse a URL and suggest ways to improve a travel site search algorithm!

17. Engagement Test

Another A/B test project. Look at test results and figure out whether engagement is going up! Also, figure out when an A/B test framework might fail!

18. On-Line Video Challenge

Figure out which videos should be promoted on the home page in order to maximize revenue from ads! Can you identify the characteristics of "hot videos"? Is virality predictable??

19. Subscription Retention Rate

Companies love subscription business models! Predict subscriber churn rate and come up with ideas to improve the company revenue via personalized offers!

20. Ads Analysis

Another classical application of data science here! Can you optimize a company ads campaign? Which metric would you choose to identify the best ads?

21. Solution: Conversion Rate

An example of a possible solution for the conversion rate challenge! You can use this solution template for pretty much any challenge where you have to build a machine learning model and extract insights from the model!


Solution for the third challenge. Another example to solve challenges which are based on looking at the data, building a model and then extract info from the model!

23. Solution: Employee Retention

An other reusable template on how machine learning can be used to predict when and why an employee decides to change job!


Are you applying for a fintech company, the risk team in any tech company or a bank? This solution template shows how to deal with transaction-related data!

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) and, more recently, on employee training (Full Course in Product Data Science and Practical Chatgpt course).

The Full Course in Product Data Science was among the fastest courses ever to reach $1 million in sales on Teachable.

In 2023, I built and sold a Chatgpt app to Colgate. Based on that experience, I created the Practical Chatgpt course.

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

Giulio is an excellent advisor for preparing for interviews. Very recommended.
Donja Darai, Sr. DS at eBay

Any Questions?