How To Prepare For Facebook Data Scientist Interview

Are y'all preparing for the Facebook data scientist interview?

Hi, I'yard Dan — a data scientist, previously at PayPal, now at Google. As an interview coach at datainterview.com, I want to assistance a candidate such as yourself ace data science interviews and land your dream part at a meridian company.

In this article, I will cover everything you lot need to know for your upcoming interview.

For more premium content, brand certain to check out my prep site @ datainterview.com.

The information scientist position at Facebook is no doubt renowned and lucrative. Co-ordinate to Levels.fyi, the typical ranges of full compensation (TC) for a data scientist role at Facebook are:

Strictly speaking on salary alone, the pay at Facebook is no dubiousness higher compared to that of data scientists nationwide, which is about $123K. It's no wonder that many aspiring information scientists dreaming of working at Facebook.

Delight note the following caveats about this guide:

The process and preparation covered in this article are based on the production data scientist function which is one of the most sought-out roles at Facebook. For other roles such as Finance, Infrastructure, and Machine Learning, stay tuned at datainterview.com for comprehensive guides such as this one!
The guide doesn't cover how to apply for a role and country the initial interview at Facebook. Tips on resume and cover letter will be covered in the near future.
The interview process at Facebook is constantly evolving. Note that the process and techniques covered hither are based on interviews conducted in the past. Interviews in the hereafter may be subject to change.

The Interview Process

In the Facebook DS interview, a candidate is funneled through a iii-stage process:

For each interview step, we will comprehend the purpose, process, sample questions, and useful tips.

Stage 1 — Recruiter Screening

The outset telephone call with Facebook is a non-technical meeting with a recruiter. The call itself is about twenty to 30 minutes, and information technology is designed for recruiters to screen whether you are a decent fit for the role you applied for.

Before the call

The recruiter sees your task application that includes a resume and an optional cover letter in the applicant tracking system (ATS). Your application is algorithmically ranked based on how well your candidacy matches the roles described in the job posts. Recruiters will typically prioritize applications with higher ranking to contact commencement.

During the call

During the call, which is well-nigh 20 to 30 minutes, the recruiter will format the meeting in the following structure:

Details about the open role and Facebook's mission — The recruiter volition describe more than details about the role expectation and team.
Candidate background — This is your adventure to sell yourself verbally. The recruiter will inquire, "Tell me about yourself." You tin can provide a high-level description of your academic and career backgrounds. Some follow-up questions include: "Why do y'all want to work for Facebook?"
Technical screening with basic SQL question — As the first line of defence force filtering out candidates who lack technical competencies, recruiters volition ask basic SQL questions such as, "Can you explicate the difference between INNER, LEFT, and OUTER JOINS?" And, "What'south the difference between UNION and UNION ALL?"
Logistics — The recruiter usually asks the post-obit: Where are you located? Are you a U.S. citizen? If not, do yous need an employer sponsorship for your visa? What are your availabilities for technical interviews?
Follow-Ups — The recruiter will detail the next steps in terms of when you should hear back and technical rounds. This is your chance to ask equally many questions equally you lot can to map out the technical interviews finish-to-cease. The more information you have, the more y'all can leverage it to prepare for interviews.

Subsequently the call

Later on the call, the recruiter will follow up with the hiring manager with notes gathered nigh the candidate's groundwork, technical screening, logistics, and civilisation fit. If the recruiter and hiring manager believe that you have potential, then they volition advance you to the commencement technical round.

Preparation Tips

To demonstrate a really good impression, make certain yous prepare the following:

Create a short elevator pitch explaining why yous want to work for Facebook.
Project a friendly and positive impression during the call.
Brush up on SQL basics.
Prepare questions to enquire in accelerate. For instance, ask questions that volition help yous assemble equally much information about the interviews as possible: how many rounds? What is the type of each round? Who is the interviewer? Gathering this data tin assist you design a prep strategy.

Stage ii — Technical Telephone Screening

The commencement technical screen is designed to test your technical bent in 45 minutes. Should you pass this round, you will proceed to the onsite rounds stage.

The technical screen for the product information scientific discipline function is unremarkably 45-minutes consisting of two question types covered:

SQL (xv–20 minutes) — You will be given access to a not-executable text editor on the Coderpad and asked to solve two to iii SQL problems involved in tabular array manipulations. Typically they inquire problems that involve table joins, singled-out clauses, window functions, and where condition.
Product-Sense (15–20 minutes) — You will be given iii to 5 open-ended questions involving metrics, analytics, and AB testing.

For sample questions, check out datainterview.com.

Preparation Tips

In training for the interview, do the following:

Exercise mock interviewing with a friend or a fellow candidate when you bring together the datainterview.com Slack study grouping.
Be in the mode of interviewing with every bit many companies as possible. The more you interview, the less yous will experience nervous and perform better over fourth dimension.
Practice solving SQL problems on a daily footing.
To cultivate product-sense requires two steps: (ane) become familiar with the Facebook core products and(2) become practice questions and run across how data scientists at FAANG companies would solve them on datainterview.com.

Stage 3 — Onsite Rounds

The concluding technical screening at Facebook consists of iv onsite (or virtual) rounds, each round consisting of 45-minutes. This is the longest and hardest phase of the interview process, and information technology will exam your ability to sustain focus and solve problems under pressure. Let'southward look at the details behind how the interview panel will assess yous in each circular:

SQL Round — Similar to the ones asked in the first technical round, the SQL questions asked in this round will require you to write an SQL logic on a non-executable text editor. Once you make sense of the problem, you will need to write and explain your solution. The interviewer will assess you lot based on your completion, solution efficiency, and communication.

Here are some questions Facebook asked:

"Given a table of user profile information and post metadata, what percent of users mail within a month of their birthdays?"

"Given a table with user id and mail id, calculate a xxx-mean solar day moving median of the mail count per user on each appointment."

Applied Data Circular — The applied data is a business case circular designed to assess how you lot would solve an open-ended data problem. The interview questions are inspired by real issues that product information scientists work on given business stakeholder'south requests.

Here are sample questions:

"How do yous know if ii friends are best friends?"

How do you lot detect false posts?

Quantitative Round — The quantitative is designed to assess your statistical and probability sense. The bug are designed to exam your fundamentals on topics such as:

Bayes Theorem
Provisional Probability
Hypothesis Testing
P-Value
Conviction Interval
Basic Distributions (i.e. Bernoulli, Binomial, Normal)

Product-Sense Round — The product-sense round at Facebook is designed to screen your technical skills on AB testing, metric-sense, and product analytics. Here are sample questions:

Product Analytics: "A success metric increased in country A, merely decreased in country B. Why?"

Metric-Sense: "How would you lot measure success on Instagram Stories?"

AB Testing: "How would you design experimentation that tests whether a new News Feed the algorithm improves engagement amid users?"

Preparation Tips

In preparation for the interview, understand the following:

Practice daily by using datainterview.com to become access to Facebook interview questions and solutions.
To gear up for production-sense questions, become familiar
Practice mock interviewing with a friend or check out datainterview.com for coaching services that will launch in the nearly future!
Be in the mode of interviewing with as many companies as possible. The more than y'all interview, the less you will experience nervous and perform better over time.
Practice solving SQL problems on a daily basis.
To cultivate product-sense requires 2 steps: (1) become familiar with the Facebook cadre products (two) go practice questions and see how experts would solve them on datainterview.com
The onsite interview volition test your ability to sustain focus for a long period of time. Once a week, spend two to three hours practicing interview questions in one sitting. This will assistance build your stamina.

Research, Research, Research!

This part of the preparation is perhaps the most underrated step in acing a data science interview, especially at Facebook. From recruiter to onsite rounds, interviewers are assessing whether you lot have a sense of Facebook's platform and its core products/features.

Merely practicing problems isn't enough. As a forerunner, yous do need to go somewhat familiar with Facebook'due south products. When interviewers ask about instance issues in product analytics and applied data rounds, yous will thank yourself for the research y'all had done prior.

Research Tip #1 — Go a User

Go familiar with both the mobile and web versions of Facebook's pop products:

Instagram
Facebook News Feed
Stories
Messanger
Groups
Posts
Profile

Spend some time making observations on how the product works and call back about what kind of data would be collected in each of the products. This volition help you if y'all were asked an open-ended question such as "How would you observe spammers? What kind of data would yous utilize?"

Enquiry Tip #ii — Keep Upwards with the Latest News

Besides, another dandy fashion to familiarize yourself with Facebook is to watch their IO talks and read the latest articles about what Facebook is up to. This provides insights into what the business as a whole cares about. When you are asked business case problems, y'all tin can tailor your responses based on current issues. This shows that yous've done your homework, which is something that the interviewer volition take a positive note of.

Research Tip #3 — Read Facebook'south Technology Blog

Lastly, read Facebook's engineering blog which contains articles on the enquiry and analysis that Facebook conducted. The web log offers clues on, not only interview questions, merely likewise potential projects y'all could be working on.

Permit'due south Practice! 😃

Now, here's the fun role of the article. Allow'due south do with a sample interview question asked in a product-sense circular by Facebook.

Facebook recently launched Stories, how would you measure success?

Bad Example

[Candidate] I've used Stories before. It's a product that allows users to publish curt-clip videos with a duration of 20 seconds at most. I retrieve there are a couple of metrics that we can rail.

[Interviewer] Okay, what are those?

[Candidate] I call up metrics such as the number of watches per user and number of reactions per user are good.

[Interviewer] Tin you call up of anything else?

[Candidate] I think those are sufficient.

Interviewer Assessment

In that location are a couple of things that the candidate failed to practise:

Failed to discuss the business problem in detail. The candidate should start past discussing what "success" means for Facebook.
The candidate failed to regard the audience in mind. Depending on the blazon of the stakeholder (analyst, product manager, marketer and e.t.c.), the types of metrics relevant will differ.
The candidate designed the metrics poorly equally "number of watches per user" is a distribution, but not a statistic such as "boilerplate number of watches beyond users per day."
The metrics are not platonic proxies for representing the "success" of the production.
The story is a two-sided app involving watchers and publishers. The candidate merely mentioned metrics involving watchers.

Good Instance

[Candidate] Thanks for the question. I'd similar to arroyo this open-ended question in the following structure. First, ask clarifying questions. Next, hash out the business context of the problem. Lastly, advise success metric(s). Is this procedure okay with you?

[Interviewer] Sure.

[Candidate] When you are asking for measuring "success," are yous looking for a single metric that serves as a proxy that represents "success?"

[Interviewer] Aye.

[Candidate] Thank you. One more question. Who is the end-user of the metric? I would imagine the metric is displayed on a dashboard.

[Interviewer] Good question. Allow's say that the end-users are the Facebook leadership.

[Candidate] Great, give thanks y'all for the clarification. I tin can tell that Facebook cares a lot almost the success of Stories every bit information technology'south a core product on the platform. It'due south probably what keeps the users engaged in the long-term, and one of the top revenue-generating products as advertisements are displayed on Stories.

[Interviewer] That's right.

[Candidate] Now, that I have some sense of the concern problem. I'd similar to propose three metrics — a single main metric that the leadership can say, "we want to increment this commuter metric past 10% YoY" and two secondary metrics to supplement the data that the primary metric lone does not provide.

[Interviewer] Dandy, proceed.

[Candidate] The primary metric should be total watch hours per month. I can imagine the stakeholder would want to understand how the Stories grew over a long period of fourth dimension, and they desire to get a sense of how this will be projected over fourth dimension. And then, looking at the total watch hours at the monthly level can provide information on how the product as a whole grew.

In terms of secondary metrics, we likewise want to track publisher behavior. So, looking at the total number of videos published per calendar month is a practiced metric. On a long-term, month-to-month footing, nosotros want to see this metric grow. More than content available means more videos that watchers tin select and consume.

Some other secondary metric involves the advert acquirement of the Story product. We want to see that this product is contributing to Facebook'southward bottomline.

Interviewer Assessment

The candidate provided a superb response:

The candidate provided a structured response: First, inquire clarifying questions. Side by side, discuss the business context of the problem. Lastly, propose success metric(s).
Understood the concern problem and audience.
Provided metrics that were well-designed based on the business concern problem.
Communicated the solution, eloquently.