Facebook Data Scientist Interview Questions | Glassdoor

Facebook Data Scientist Interview Questions

Updated Oct 18, 2018
164 Interview Reviews

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Helpful (22)  

Data Scientist Interview

Anonymous Interview Candidate
No Offer
Neutral Experience
Difficult Interview

Application

I applied through an employee referral. The process took 4 weeks. I interviewed at Facebook.

Interview

One call with the recruiter and one phone interview with a Data Scientist and moved on to on-site interview with 5 rounds of interviews. In the phone interview, it's mostly brainstorming metrics and an SQL query question. The 5 rounds of on-site interviews includes 2 SQL, 2 A/B testing and 1 Math interviews.

Interview Questions

  • If there's a new feature that attracts more pop stars to use it, how do you evaluate whether this feature is successful or not?   1 Answer

Other Interview Reviews for Facebook

  1. Helpful (4)  

    Data Scientist Interview

    Anonymous Interview Candidate in San Francisco, CA
    No Offer
    Positive Experience
    Average Interview

    Application

    I applied through a recruiter. The process took a week. I interviewed at Facebook (San Francisco, CA) in December 2017.

    Interview

    I had two phone interviews with the recruiter. She was very nice, informative and helped me set up for success. I had to pull out after that due to other offer.

    Interview Questions

    • Common statistical and python related questions.
      1) How do you proof that males are on average taller than females by knowing just gender or height.
      2) What is a monkey patch
      3) How do you get the count of each letter in a sentence   5 Answers

  2. Helpful (2)  

    Data Scientist Interview

    Anonymous Interview Candidate
    No Offer
    Neutral Experience
    Difficult Interview

    Application

    I applied in-person. The process took a week. I interviewed at Facebook in March 2018.

    Interview

    Was contacted by a Facebook recruiter and then the resume exchanged hands when finally got a call from Infrastructure team. Recruiter herself asked screening questions from sql, statistics and programming, trivial ones.

    It was followed by a phone interview. It was from 3 areas in sql, programming and machine learning. Recruiter was clearly interviewing to test the limits. There were 3 questions on sql, 1 on programming and 2 questions on machine learning concept. The focus on machine learning was quite less and primary focus seemed to be on sql and programming.

    Sql questions were on group by and joins. The first question needed a self join which i didn't get at first, but the interviewer was helpful. The other 2 questions were straight forward group by and join questions .

    programming question was a bit unexpected for doing in 20 mins. Was given a log file of format
    id, accepted, id1,id2,id3
    id, rejected, id5
    id3,request, id6

    and was asked to create a network graph from it. I guess the interviewer wanted the result in simply a dictionary , but started with what will be the best data structure to store it, to which i answered bi directional graph and then asked me to code the graph, which got me confused b/w the linked list approach and the normal dictionary approach and ended up taking more time. In midway he said that he understood my approach and moved to machine learning.

    In machine learning the questions were between bias variance trade off and PCA . In PCA he went into detail as in what method is used to decompose matrix, what is the significance of first principal component and in the end what is the relationship between the first and second principal component. I got stuck at the relationship between first and second principal component.

    I got rejected. My best guess is because of the programming question. Recruiter had suggested that phone interview will be around basic data processing question, so wasn't expecting a network graph question at the phone interview level. But guess it's facebook :)

    Interview Questions

    • To create a network graph from a log file in 20 mins. Guess the interviewer wanted a simple dictionary as a data structure but confused me with calling it a network graph repeatedly. If he indeed wanted it like a graph where all properties such as pre order , in order traversal could be applied. It's no way a 20 min question.   3 Answers
  3. Helpful (2)  

    Data Scientist Interview

    Anonymous Interview Candidate in Boston, MA
    No Offer
    Negative Experience
    Average Interview

    Application

    I applied through a recruiter. The process took 2 weeks. I interviewed at Facebook (Boston, MA) in March 2018.

    Interview

    HR reached out to me on linkedin for data scientist infrastructure position. Scheduled an interview after 2 weeks. This was a technical round with sql, python and statistics questions. The interview lasted for an hour with live coding. The interviewer was very nice and i answered all of the questions. I was not sure about logic for one of the questions on python. Rest were right. I did not make it to the next round. I am sure what went against me but assume python was the issue.

    Interview Questions

    • A table has a column with full names(e.g. 'Tom Hardin'). write a python code to get distinct first names(i know its super easy in sql)   5 Answers

  4. Helpful (2)  

    Data Scientist Interview

    Anonymous Interview Candidate in Menlo Park, CA
    No Offer
    Positive Experience
    Average Interview

    Application

    I applied through a recruiter. The process took 4+ weeks. I interviewed at Facebook (Menlo Park, CA) in January 2018.

    Interview

    I was contacted by the recruiter with whom I had a brief 10-15 minute phone call. Then we went ahead with a virtual interview with another data scientist. The online interview consisted of writing code in a text editor answering some data analysis questions such as how do you measure user engagement, how do you measure the effectiveness of a new feature. The interviewer was looking more for the thought process than actual execution of the code.

    I got through the online interview and was scheduled for the onsite interview loop consisted of five interviews of 30 minutes each. Two required product analytics brainstorming, one was statistics and probability, and two more were performing ETL using SQL and also performing analysis using SQL. There was a lunch break of an hour in between.

    I had a great experience throughout the interview process and the recruiter helps out a lot by emailing preparation materials and calling to discuss the material. Unfortunately I did not get through the last interview. I was not given a reason, just that there were many applicants.

    Interview Questions

    • How do you calculate monthly active users, churned users and resurrected users from a user activity log with userID and DateTime   7 Answers

  5.  

    Data Scientist Interview

    Anonymous Interview Candidate
    No Offer
    Positive Experience
    Difficult Interview

    Application

    I applied through a recruiter. The process took 2+ weeks. I interviewed at Facebook in January 2018.

    Interview

    In email, they include the description of next interview in advance. No surprise. I got 1 hr phone interview and 2 technical phone interviews. There are 3 parts in Phone interview: SQL, Data analytics with python, Machine learning and deep learning

    Interview Questions


  6. Helpful (3)  

    Data Scientist Interview

    Anonymous Interview Candidate
    No Offer
    Positive Experience
    Easy Interview

    Application

    I applied through college or university. I interviewed at Facebook.

    Interview

    Initial interview was relatively simple. Just questions about what aspects of available data you would use to answer certain business questions or anomalies. One relatively complex SQL question. Should've brushed up more on my SQL! What you come to find out is that the "Data Scientist" role with Facebook is really just more of a Data Analyst type role.

    Interview Questions

    • Say you notice a surge in average activity among users but the number of users is down, how would you explain this?   2 Answers

  7. Helpful (7)  

    Data Scientist Interview

    Anonymous Interview Candidate
    No Offer
    Negative Experience
    Difficult Interview

    Application

    I applied through a recruiter. The process took 4+ weeks. I interviewed at Facebook in February 2018.

    Interview

    Was first approached by an internal recruiter at Facebook via a LinkedIn message. Within a week I did an initial 15 minute screening interview in which the recruiter asked me if I had experience/competence in SQL, Python, or R.

    Afterwards I was sent around 2-3 emails containing study material, along with advice on how to prepare for a 1-on-1 video interview I was to have. After I reviewed the material I was to schedule a time to interview with a Data Scientist Manager.

    The interview was a mix of analytical problem solving and technical. It was enjoyable getting to interact with someone very talented in their skills and showcased Facebook's level of talent well. During the interview there was a degree of guidance as I navigated the technical components and analytical portion of the interview, which was expected per the interview prep material.

    Personal Analysis of Interview:
    It was great getting to be challenged both technically and analytically from the top talent around, and felt that I showcased my problem solving capabilities well but undersold my technical skills. Not sure I would have done any studying differently, I am just not at the technical level that is required at a company like Facebook.

    However, it has been nearly a month since my interview and haven't received any communication from the HR department despite multiple (3) follow up emails on my behalf. Very disappointing, as I had a wonderful experience leading up to that. This experience has definitely soured the experience and desire to work at Facebook. Hopefully this is an isolated case.

    Interview Questions

    • Suppose the Recommended Friends team has updated the algorithm to analyze if the new algorithm is better than the old algorithm.   1 Answer
    • Given the following tables how would you know who has the most friends

      REQUESTS
      date | sender_id | accepter_id

      ACCEPTED
      accepted_at | accepter_id | sender_id   8 Answers
  8. Helpful (3)  

    Data Scientist Interview

    Anonymous Interview Candidate
    No Offer
    Positive Experience
    Average Interview

    Interview

    Recruiter contacted me out of the blue on LinkedIn, set up a quick chat on the phone. He proceeded to ask basic stats questions which I was totally unprepared for unfortunately.

    Interview Questions

    • Facebook has personal information such as gender and height. If I were to make a claim that men were taller than women, how would you go about proving/disproving this claim?   2 Answers
    • What is a Z-test? When would you use a Z test over a T test?   Answer Question

  9.  

    Data Scientist Interview

    Anonymous Interview Candidate
    No Offer
    Neutral Experience
    Average Interview

    Application

    I applied online. The process took 3 weeks. I interviewed at Facebook in January 2018.

    Interview

    - Phone call with a recruiter at Facebook. I applied online and a recruiter contacted me after several weeks.
    - Technical interview with one of employees at Facebook
    - On-site interviews at Facebook HQ

    Interview Questions


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