Facebook Data Scientist Interview Questions | Glassdoor

Facebook Data Scientist Interview Questions

Updated May 22, 2017
88 Interview Reviews

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Helpful (2)  

Data Scientist Interview

Anonymous Interview Candidate in New York, NY
No Offer
Negative Experience
Difficult Interview

Application

I applied through an employee referral. The process took a week. I interviewed at Facebook (New York, NY) in October 2016.

Interview

was refused directly within one week after application. sign......why don't even give applicant an interview opportunity? someone referred me to that intern, but the resume still is not being successful....

Other Interview Reviews for Facebook

  1. Helpful (5)  

    Data Scientist Interview

    Anonymous Interview Candidate
    No Offer
    Neutral Experience
    Difficult Interview

    Application

    I applied through a recruiter. The process took 4+ weeks. I interviewed at Facebook in May 2016.

    Interview

    The technical interview was tough. I was not expecting another data scientist interviewing me about a hypothetical feature -- a credit card info pop-up. Then, the next part was more of a product development question -- how would one develop the Like, Love, Sad feature.

    The competitive nature of Facebook work environment seems to be affecting the interview process. Even though the recruiters are generous about giving clues for the prep, the data scientist interviewer came across as arrogant, esp when they found out I did not have a PhD like them.

    Interview Questions

    • How would one develop the Like, Love, Sad feature?   3 Answers

  2. Helpful (58)  

    Data Scientist Interview

    Anonymous Employee
    Accepted Offer
    Positive Experience
    Difficult Interview

    Application

    I applied through an employee referral. I interviewed at Facebook.

    Interview

    Got the interview via internal referral. First step was with the HR. It was mainly to discuss about my interests and to decide which team I should be applying for. It was nice and it felt like HR was genuinely trying to understand what I like to then match me to the appropriate team.

    After a couple of days I got an email from HR saying I would be interviewing with the Personalization team and that the first step would be to solve a takehome test. I won't describe the challenge, but it is very similar to one that can be found on the book "A Collection of Data Science Takehome challenges". Since I had prepared on that book, I could solve it fairly easily.

    The next step was onsite interview with team members. The onsite interview was really long and it involved a lot of open ended questions (i.e. how would you do this? what kind of problems do you think you will encounter with this approach? etc.). After you would describe your approach, they would go into details a lot to make sure you actually have a clear idea of how to take the project from start to end.

    It was a really hard interview, but it is facebook, so it is kinda expected. I got an offer and salary was really high so I was just happy to accept!

    Interview Questions

    • Sent a takehome test related to machine learning and variable importance   5 Answers

  3. Helpful (5)  

    Data Scientist Interview

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

    Application

    I applied through a recruiter. The process took 3 weeks. I interviewed at Facebook (Menlo Park, CA) in February 2015.

    Interview

    Interview process is long and drawn out. As expected, of course, for large tech companies these days. Unfortunately, data science interviews do not necessarily reflect the ability of applicants to do the job they are applying for, and do not reflect a normal day's work. More challenging questions about coding than would make sense for anyone with an analysis/stats background. Instead difficult questions should be focused on problem solving skills

    Interview Questions

    • Write a sorting algorithm for a numerical dataset in Python.   9 Answers

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  5. Helpful (1)  

    Data Scientist Interview

    Anonymous Interview Candidate
    No Offer
    Positive Experience
    Difficult Interview

    Application

    I applied through a recruiter. I interviewed at Facebook.

    Interview

    A recruited reached out to me and I had a call with her. This was followed by a technical screening with a data science manager. The last step was a full round of interviews onsite.

    Interview Questions

    • They asked SQL questions, probability and product analysis   Answer Question

  6.  

    Data Scientist Interview

    Anonymous Interview Candidate
    No Offer
    Neutral Experience
    Difficult Interview

    Application

    I applied through a recruiter. I interviewed at Facebook in May 2017.

    Interview

    Recruiter conversation and phone screen, one phone screen via video call.
    At first I was pleased because the recruiter sent a detailed preparation guide and I had a few weeks to prepare. I spent some time preparing nearly every day, making sure I was well versed in R, which was the language that I requested for the phone screen.
    The recruiter emphasized that product sense was important, so I spent time thinking and reading about metrics necessary to evaluate products and how that may be applied to Facebook.
    In the end, I think I would have been better off without the interview preparation guide, as it turned out to be completely misleading.
    The interview contained no probability questions, even though that was mentioned as part of it, and no product sense questions. There was only one fairly straightforward data engineering type question.
    The rest was simply SQL questions, even though I had requested R as the language. I was able to use R to answer the SQL question, and then for the second follow-up questions switched to SQL, but really the type of question would be best answered with SQL.
    The interview guide said that if you requested R, then they would be testing dplyr/apply functions, but that wasn't really true.
    The SQL question was not straightforward, but fairly challenging. I was thrown off because I was expecting a data analysis question using R, and I was a bit nervous under pressure. I was able to answer the questions, but not without stumbling a bit.
    The whole process was frustrating because I write fairly complex SQL questions often as part of my job, and have never had a query I couldn't figure out. But under the pressure of the interview, I didn't perform spectacularly. I wish I had not spent time on the other parts of the interview prep and just focused on SQL, and I probably would have been more successful. So beware the prep guide may lead you astray.

    Interview Questions

    • SQL question
      One basic data engineering related question  
      1 Answer

  7.  

    Data Scientist Interview

    Anonymous Interview Candidate in London, England (UK)
    No Offer
    Positive Experience
    Difficult Interview

    Application

    I applied through a recruiter. The process took 2 weeks. I interviewed at Facebook (London, England (UK)) in November 2014.

    Interview

    First quick skype call, with general analytics related questions + little sql exercise.

    Second round in person. A round of five separate interviews at Facebook HQ in Euston, each with a different flavour, some more general analytics/BI, some more technical (e.g. coding exercise, sql etc).

    Some interviewers were very approachable and easy to talk to, some others much less. There was one case when I honestly thought the person interviewing me had something against me or was upset for some reason, as their behaviour was very rude and confrontational. I am a very peaceful person usually so I let it go.
    Probably Facebook asked some random employees to come over from their HQ in the US to do these interviews in change of a little paid vacation in London. I suppose some of them were affected by the jet lag more than others.

    Overall it was a good experience; it looked like the day was very well organised.

    Interview Questions

    • Imagine we see a lot of users filling up a form but not submitting it, why would it be the case and how would you use data to finding it out?   3 Answers

  8.  

    Data Scientist Interview

    Anonymous Interview Candidate in Vancouver, BC (Canada)
    No Offer
    Positive Experience
    Difficult Interview

    Application

    I applied through an employee referral. The process took 1 day. I interviewed at Facebook (Vancouver, BC (Canada)) in December 2016.

    Interview

    First a brief introduction of yourself. Then why you choose facebook. The following is an online coding question using mysql. Then question about like/dislike system in the facebook. How to choose emotions and any problems in the A/B test. This question is quite hard and I didn't get it until the interviewer gave a lot of hints.

    Interview Questions

    • How to choose emotions in like/dislike systems and any problems in the A/B test.   3 Answers

  9. Helpful (59)  

    Data Scientist Interview

    Anonymous Interview Candidate in Menlo Park, CA
    Declined Offer
    Negative Experience
    Difficult Interview

    Application

    I applied online. The process took 6 weeks. I interviewed at Facebook (Menlo Park, CA) in February 2017.

    Interview

    I applied online in late December and then spoke to a recruiter for about 15 minutes in early January. I was scheduled for an in-person interview in mid January where I interviewed with one data scientist in a 1:1 interview for an hour for the first round. Another recruiter then called me for a 30 minute prep for the 2nd round. The final, 2nd round interview was about 5 weeks later in late February, with 6 data scientists over 4 hours in the afternoon. I got an offer but it was for a lot less than I was expecting, and we couldn't bridge the gap enough for it to be worth it.

    Everyone seemed relatively nice, although I could tell that a lot of the questions are really designed to trip you up, like they want you to miss some detail or edge case. My advice would be to pay attention to every little bit of minutiae regarding the question, make sure you're staying on task, write on the whiteboard, and explain your thoughts. Industry word is that data science at Facebook is not what it once was and is more of a product data analyst role now, so make sure you're really into Facebook products because that's what you'll be analyzing.

    Also, I didn't get a single question about dice, cards, or any other brain teaser type questions. All these mentions of NDAs are missing the point of Glassdoor, people can be a little more verbose than "various questions". You can't trademark an interview question or claim it's a trade secret.

    Interview Questions

    • How would you measure the health of Mentions, Facebook's app for celebrities? How can FB determine if it's worth it to keep using it?

      If a celebrity starts to use Mentions and begins interacting with their fans more, what part of the increase can be attributed to a celebrity using Mentions, and what part is just a celebrity wanting to get more involved in fan engagement?  
      5 Answers
    • There is a table that tracks every time a user turns a feature on or off, with columns user_id, action ("on" or "off), date, and time.

      How many users turned the feature on today?
      How many users have ever turned the feature on?
      In a table that tracks the status of every user every day, how would you add today's data to it?  
      5 Answers
    • If 70% of Facebook users on iOS use Instagram, but only 35% of Facebook users on Android use Instagram, how would you investigate the discrepancy?   5 Answers
    • How do you measure newsfeed health?   2 Answers
    • If a PM says that they want to double the number of ads in Newsfeed, how would you figure out if this is a good idea or not?   3 Answers
    • We have two options for serving ads within Newsfeed:
      1 - out of every 25 stories, one will be an ad
      2 - every story has a 4% chance of being an ad

      For each option, what is the expected number of ads shown in 100 news stories?
      If we go with option 2, what is the chance a user will be shown only a single ad in 100 stories? What about no ads at all?  
      7 Answers
    • How do you map nicknames (Pete, Andy, Nick, Rob, etc) to real names?   3 Answers
    • Facebook sees that likes are up 10% year over year, why could this be?   4 Answers
    • How many high schools that people have listed on their profiles are real? How do we find out, and deploy at scale, a way of finding invalid schools?   4 Answers

  10.  

    Data Scientist Interview

    Anonymous Interview Candidate in Palo Alto, CA
    No Offer
    Negative Experience
    Difficult Interview

    Application

    I applied through a recruiter. The process took 3+ months. I interviewed at Facebook (Palo Alto, CA) in December 2016.

    Interview

    The interview process was unbelievably long and redundant. Over 3 months, in total, I think I had 4 phone screens, ~10 on-site interviews (across 2 separate days). Many were fairly redundant and covered the exact same areas. It came across as formulaic and bureaucratic. The recruiters I talked to, while fairly responsive, constantly over-promised how quickly we could advance to the next step of the process. I ended up taking another offer before hearing the final decision.

    Interview Questions

    • Several interviews about SQL, product, business, stats   Answer Question

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