How to ace the Facebook data scientist interview
Tags: datascience, database, sql, career
Published: 2021-02-18 23:22:10

Facebook is a dream company for many data scientists. However, many are caught off guard by the unique business-focused interview process and role for data scientists at Facebook.
 
Today, we'll show you what to expect and help you practice the data science interview questions you'll need to ace your Facebook data science interview.
 
**Here’s what we’ll cover today:**
 
* [Data Science at Facebook](#overview)
* [Data science interview process](#process)
* [The technical screen](#technical)
* [Onsite interviews](#onsite)
* [How to prepare for your interview](#prep)
 
 
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<h4><b> Ace the data science interview the first time </b></h4>
 
Practice dozens of hands-on practice problems and brush up on your fundamentals all in one place.
 
<b> [Grokking Data Science](https://www.educative.io/courses/grokking-data-science) </b>

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<a name="overview"></a>
 
## Data Science at Facebook
Data scientist is a senior role at [Facebook](https://www.educative.io/blog/cracking-top-facebook-coding-interview-questions) that focuses heavily on business problems rather than engineering. Your focus will be product and market analysis to help Facebook make data-driven business decisions. This makes Facebook's data science jobs a unique hybrid of product data analysts and data scientists.
 
**Your day to day responsibilities will include:**
- Use product and market trends to find growth opportunities, set appropriate team goals, and guide product development to meet emerging needs.
- Maintain good product sense and understand how user needs are developing.
- Act as a medium between business and engineering teams to influence new features and future marketing. 
- Leverage Facebook's [huge data sets](https://www.educative.io/blog/what-is-big-data) to generate proposed next moves and create [approachable visuals](https://www.educative.io/blog/d3js-tutorial) that convey these to executives.
- Parse and weight data based on statistical significance, geographic region, bias, target populations, and potential for positive results.
 
These unique challenges will expose you to varied practical applications of data useful for quickly advancing your resume and career. The role also comes with one of the highest starting salaries for a non-executive position at Facebook, ranging anywhere from **$120k-$190k** according to Glassdoor. 
 
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### Application Requirements

Facebook is looking for candidates with a mixed background in both computer science and business analytics.
 
- Proficiency in Python or Java
- Experience with artificial intelligence and [machine learning algorithm design](https://www.educative.io/blog/cracking-machine-learning-interview-system-design)
- BS/BA in Computer Science, Mathematics, or other related technical fields (or [relevant bootcamp](https://www.educative.io/blog/coding-bootcamp))
- 2+ years of experience in the data warehouse space
- 2+ years of experience writing [SQL query statements](https://www.educative.io/blog/what-is-database-query-sql-nosql)
- 2+ years of experience with [schema design](https://www.educative.io/blog/what-are-database-schemas-examples)
- 2+ years of experience with a [OOP programming language](https://www.educative.io/blog/object-oriented-programming)
- 2+ years of experience with ETL design
- 2+ years of experience working with [MapReduce](https://www.educative.io/blog/what-is-big-data) or MPP systems
- Experience identifying deliverables, gaps, and inconsistencies in product/market data
- Experience communicating data with internal clients

![Alt Text](https://dev-to-uploads.s3.amazonaws.com/uploads/articles/3zfn6r6613x9oag7rwdf.PNG)

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<a name="process"></a>
 
## Data science interview process
The Facebook data scientist interview has **3 parts**: the initial phone screening, the technical screening, and onsite interviews.
 
Throughout the various stages, Facebook interviewers will be testing how you think when approaching problems. Projecting your strong problem-solving skills and showing your consideration for possible obstacles is essential. 
 
Interviewers will be listening for how your solutions and processes are **optimized for scalability.** Facebook collects a lot of data compared to many other tech companies, so they're especially interested in your ability to work with [big data](https://www.educative.io/blog/what-is-big-data) and vast structured databases.
 
Finally, interviewers will want to see you approach problems from a **product perspective,** rather than just engineering. This means focusing on the practical application of suggestions, *"what metrics can we use to gauge user involvement"*, rather than the technical aspects like "how can we more efficiently store data". 

These technical aspects are still important to mention but your priority should always match the business/product focus of the role.
 
<br>

### Initial Screening

Set up on LinkedIn or by email, the initial screening is a 30-minute phone interview with a recruiter to discuss Facebook, your desired position/team, and clarify that you're interested in the unique business-focused data science role that Facebook offers. 
 
This is where you can hear more about the role and decide if it's a good fit for you.

![Alt Text](https://dev-to-uploads.s3.amazonaws.com/uploads/articles/7xt7otawt70ovhj33h2c.png)

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<a name="technical"></a>
 
## The technical screen
This is another virtual screening that tests your product sense and technical skills with SQL. 
 
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### Product Sense
 
The product sense portion is a video interview with a current data scientist at Facebook designed to assess your ability to approach and breakdown a problem. 

Finding the correct solution is not as important as effectively breaking down the problem, considering all the influencing factors, and **presenting a course of action** (not just data findings).
 
When preparing for this portion, practice:
 
- Deconstructing large problems its root causes and understanding the context
- Explaining your findings and suggested course of action confidently and articulately
- Presenting a hypothesis for your findings and explaining what leads you to that conclusion
- Translating data findings into actionable advice
- Engage with Facebook products as someone looking to improve the product rather than just a user
 
Here are some questions you can expect to encounter:
 
- How would you set up an experiment to evaluate a new product's performance?
- How would you measure success for separate parts of the product, such as Facebook Live vs. client advertisements?
- How could you use current and past data to anticipate features users will want in the future?
- How would you prepare to access a new product launch?
 
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### Technical
 
In this section, you'll be given a data set and two questions to solve in code over 20 minutes (10 minutes per question). 

You must solve both questions in SQL or [Pandas](https://www.educative.io/blog/python-pandas-tutorial) code using a code editor called Coderpad. However, **SQL is preferred** as it is the standard for Facebook's data science tools. 

>You'll not be able to execute your code, so practice SQL syntax to ensure minimal syntax errors.
 
Along with coding each solution, you'll have to explain the application and shortcomings of each solution. Facebook, more than other heavy data science companies like [Amazon](https://www.educative.io/blog/crack-amazon-coding-interview-questions), is looking for data scientists with excellent communication skills. 
 
For example, you may receive two tables with information about a certain Facebook Group's activity: a usage log that contains data on each person's time spent on the page for the last year and another table that includes the name, date of birth, occupation, and hometown of each member.
 
**You'd then be asked to create SQL programs to find:**
- How does usage differ by age in this group?
- What occupation had the highest usage difference between Friday and Saturday?
- Which factor seems to be most linked to usage?
- What percentage of users visit the group on their birthday

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> #### Keep prepping for your interview.
> 
> Prepare for your interview right with dozens of hands-on practice problems and a comprehensive data science project. Educative's text-based courses are made by current data scientists to let you know exactly what to expect on interview day.
>
> <b>[Grokking Data Science](https://www.educative.io/courses/grokking-data-science)</b>

</div>
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![Alt Text](https://dev-to-uploads.s3.amazonaws.com/uploads/articles/1gw35cf9g7mgg1teipsy.PNG)

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<a name="onsite"></a>
 
## Onsite interviews
The final stage of the interview is a **2.5 hour series of interviews** at either the Menlo Park, Seattle, or the New York Facebook campus. There are 4 different 30-minute interviews that each cover a different case study. There's also a 30-40 minute lunch break to discuss the role with a current data scientist. 

You have the entire 30-minute interview to answer each question:
- 1 SQL technical question
- 1 product interpretation question
- 1 quantitative analysis question
- 1 applied data question
 
The **SQL technical question** will be similar in format to the technical screening questions; you'll receive a data set and be asked to solve problems using SQL. However, this SQL question tends to be more difficult and has a longer solution than those in the technical screening.
 
The **product interpretation question** asks you to measure product performance with details like target KPIs and how to implement a/b testing. You might be asked just to walk through this or you may have to create a high-level plan of the implementation. 
 
>An example problem for this would be:
 >
>"How would you measure the performance of *X* new feature?"
 
The **quantitative analysis question** is a basic statistics problem that tests if you understand the basics of statistical data analysis. Many candidates find this to be the easiest part of the interview as it is simply a baseline that you've not forgotten the fundamentals.
 
> Example questions for this are things like:
> - What is Bayes' theorem and when would you use it?
> - What is hypothesis testing?
> - What is p-value and how do you interpret it in context?
> - List assumptions about data in the context of linear regression.
> - How would you explain the application of probability to your [product manager](https://www.educative.io/blog/lean-product-management)?
 
The **applied data question** asks you to consider a solution at a high-level. You'll outline your process, list any assumptions you have, describe possible shortcomings and how you've prepared for them, and explain how you reached your conclusions. The interviewer will ask follow-up questions during the process to see how deeply you're thinking about this solution.
 
> Questions for this section are intentionally broad, such as:
>- Do people interact more or less on Facebook with their siblings?
> - How would you measure interaction?
> - How would you determine if people are siblings?
> -  How could Facebook use this information?
 
**Or**
 
>- How does activity vary depending on the season?
> What region/s are you looking at?
> How would you weight activity, is a comment worth more than a like?
> - What factors would you use to distinguish users?
> - How could Facebook use this information?
 
Between two of these interviews, you'll get a casual 30-40 minute interview with a current data scientist to ask them about their day-to-day responsibilities, challenges, and anything else you're curious about. 

This is essentially a [behavioral interview](https://www.educative.io/blog/behavioral-interviews-how-to-prepare-and-ace-interview-questions) to see if you've got the right mindset and excitement to fit the company. Ask them insightful questions that show you're thinking about the job, and turn your charm up to 11!
 
> Some good questions to ask are:
> - What was the most difficult project of your career and how did you solve it?
> - What are the unique benefits of being a Facebook data scientist?
> - What tips do you wish you had when you started working at Facebook?
> - What is your favorite Facebook feature to work on and why do you like it?

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<a name="prep"></a>
## How to prepare for your interview 
As you approach your interview, remember:
1.  Failing one part of the interview does not mean you won't get the job, keep your confidence up.
2.  Recruiters are evaluating your attitude and friendliness as much as your skills, don't forget your behavioral interview skills.
3. Brush up on your machine learning, SQL query fundamentals, and statistics fundamentals to make sure you don't make any avoidable mistakes.
 
The best way you can prepare for this interview is with **hands-on practice**. 

To let you brush up on your fundamentals and data science skills right, Educative has created the course [**Grokking Data Science**](https://www.educative.io/courses/grokking-data-science). This course includes over 10 hours of learning material from statistics fundamentals, to advanced machine learning. In the end, you'll cement your learning with experience by completing a real-world machine learning project. 
 
With this course, you'll be able to walk into your Facebook interview with confidence!
 
*Happy learning!*
 
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### Continue reading about data science interviews
- [Crack the top 40 machine learning interview questions](https://www.educative.io/blog/top-machine-learning-interview-questions)
- [Cracking the top 40 Facebook coding interview questions](https://www.educative.io/blog/cracking-top-facebook-coding-interview-questions)
- [Anatomy of a machine learning system design interview question](https://www.educative.io/blog/anatomy-machine-learning-system-design-interview)