Facebook Data Scientist Interview Questions

Updated Oct 17, 2014
Updated Oct 17, 2014
18 Interview Reviews

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4 people found this helpful  

Data Scientist Interview

Anonymous Interview Candidate in Palo Alto, CA
Anonymous Interview Candidate in Palo Alto, CA
Application Details

I applied online. The process took 2 weeksinterviewed at Facebook in August 2011.

Interview Details

I have a PhD in computational neuroscience / psychology. The Data Scientist position looked perfect for me because of my interest fitting models to large datasets describing human behavior. The HR person was nice. The interviewer was someone from the data science team-- nice and very young. He had me go up to the white board and write C++ code to answer a few questions. As a PhD, I was expecting research type questions, not coding. So I got a bit nervous. I didn't fully understand all of his questions and he helped me. I left feeling kind of annoyed. It probably wasn't the right job for me because I am not a software engineer.

Interview Questions
  • How would add new Facebook members to the database of members, and code their relationships to others in the database?   Answer Question
No Offer
Negative Experience
Difficult Interview

Other Interview Reviews for Facebook

  1. 7 people found this helpful  

    Data Scientist Interview

    Anonymous Interview Candidate in Menlo Park, CA
    Anonymous Interview Candidate in Menlo Park, CA
    Application Details

    I applied online. The process took 6 daysinterviewed at Facebook.

    Interview Details

    1. Phone interview with recruiter. They're looking for enthiusiasm!

    2. Onsite with boss and manager. They don't emphasize that you NEED to know how to code, but it certainly helps. You really ought to understand SQL well enough to do JOINS, UNIONS, GROUP BYs

    3. Onsite with various people (engineer, product manager, two analysts/data scientists). Various Python and SQL questions. Was also asked to create or take an existing product on Facebook and come up with ways to drive engagement.

    Interview Questions
    • Write a function that takes in two sorted lists and outputs a sorted list that is their union.   View Answers (6)
    Negotiation Details
    I accepted the offer immediately, it was exactly what I was looking for.
    Accepted Offer
    Positive Experience
    Difficult Interview
  2.  

    Data Scientist Interview

    Anonymous Interview Candidate in Menlo Park, CA
    Anonymous Interview Candidate in Menlo Park, CA
    Application Details

    I applied through an employee referral. The process took 5 weeksinterviewed at Facebook in August 2013.

    Interview Details

    Submitted resume through employee referral. Received call from recruiter about three weeks later. After initial phone screen with recruiter set up phone interview with two people there (back to back 30 minute one on one interviews). One of the interviews was on analytics - a statistics questions and measuring the performance of their products. The other was technical, involved sorting list.

    Like 8 days later, recruiter got back in touch with me saying they were going to bring me on-site for an interview. They set up a flight and hotel room for me. On-site was five one-on-one 30 minute interviews. Two technical, two analytics, and one on product. Really seemed interested in how I would measure performance of Facebook products and use data to identify problems.

    Interviews set up to run from 9:00am - 11:30am. They just grabbed me from the lobby at 8:45, put me in a room that the interviewers came to, then dropped me back off in the lobby after the last interview without showing me around at all. Friend came down to get me afterwards to give me a tour and grab lunch.

    Recruiter said would let me know decision within 2 days but no news til 8 days later. Didn't get an offer.

    Overall, experience was pretty good though the recruiting staff seemed overworked and often missed their own deadlines.

    Interview Questions
    • What would you add to Facebook and how would you pitch it and measure its success.   Answer Question
    No Offer
    Positive Experience
    Difficult Interview
  3. 10 people found this helpful  

    Data Scientist Interview

    Anonymous Interview Candidate in Menlo Park, CA
    Anonymous Interview Candidate in Menlo Park, CA
    Application Details

    I applied online. The process took 3 weeksinterviewed at Facebook.

    Interview Details

    This was for the data scientist/business analytics role.

    a little background on me: I just received my bachelors. I do not know if what I say will necessarily be applicable to people in a different situation.

    Starting from the beginning: I applied cold with my resume through their website. Then there was an optional coding question. Pro tip: Do it.

    The question was a bit more difficult than your average weed out question. The question was a game theory - esque question, e.g. "given these rules of a game and a starting point, tell me whether player 1 or player 2 will win". They gave me 2 hours for the question. I spent about 45 minutes thinking/writing code (final solution was about 25 lines of python code, the idea was the tricky part), then 15 minutes commenting code and trying to make it look pretty. Another pro tip: The question is timed. try to finish as fast as possible while still giving a solid solution/explanatory comments.

    Within a few days (maybe one or two) I was contacted by a Facebook recruiter to set up a a phone or 1:1 onsite interview, I opted for the phone interview. The recruiters are awesome/responsive. If they're not responding they're likely in meetings, don't fret. You will be talking with the recruiters quite a bit. They set up phone calls with you (not interviews) just to get a sense of who you are throughout the process. Be friendly and convey your excitement.

    The phone interview: It was not crazy difficult for me. There's obviously no hard tips I can give you aside from 1) try not to let the phone go silent, always be telling them what you're thinking about, even while writing code. Justify it line by line, this way if you mess up along the way they can point it out before you dig the hole too deep. Then again, don't expect them to point out every error you make. 2) Expect a mathematical question. It won't be some stupid straight coding question like "reverse the words in this string".

    This interview was a while ago, but i'll try to recall the general structure of it. They ask you some sql like query questions. I didn't know sql, so I answered in python. They asked me to code the question in a shared doc, then after I got the right solution they asked me to answer (verbally) a mathematical elaboration of that question. This elaboration lead into a discussion, and then questions from my end.

    Soon after I was asked to come in for an onsite interview. It was a greet with my recruiter, then 5 interviews with no break for lunch (which I would recommend). The interviews were a lot of fun. It was 2-3 data science type of people, a product manager, and a staff data scientist.

    I signed an NDA so I can't tell you what they asked me but the recruiter will tell you the general type of questions they ask. Some questions involved writing code, some didn't. All of them felt like a discussion. (e.g. I offer an important component about answering the question, and they say "but what about this case where your component doesn't help?" and you iterate.)

    They work heavily with sql, but they don't count it against you if you don't know it. Use whatever language you feel most comfortable in.

    Tips:
    Don't be nervous. Smile, I can't say this enough. If you act like you're being shot at it will make the process painful. I even made a few jokes and so did my interviewers. Don't be afraid to laugh, this isn't an interrogation. If you're excited about the job, they'll be able to tell. Don't beat around the bush/avoid questions. I had 10 minutes left in an interview and my interviewer asked if I wanted to stop and ask him questions, I said "no, I like your questions, let's keep going". That kind of excitement will shine through and make the interview feel natural. Just keep calm and keep it conversational. Ask for clarification on a question if you're even slightly unclear about the problem. Try to keep talking/express what you're thinking during the entire process. Also, be creative, they're looking for that.

    Most importantly, try to honestly convey your passion/excitement for the job. These guys love their job and want to see that you will too. That being said, don't fake it. Your interviewers are ridiculously smart so you won't be able to fool them.

    Good luck!

    Interview Questions
    • They honestly give you a good feel for the types of questions they'll be asking. No surprises. "Most difficult" is so subjective it's meaningless in this context. I hope you're good at math/computer science. If you've had some meaningful machine learning experience, you'll be set.   Answer Question
    Negotiation Details
    I didn't negotiate. Their offer was generous.
    Accepted Offer
    Positive Experience
    Difficult Interview
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  5. 17 people found this helpful  

    Data Scientist Interview

    Anonymous Interview Candidate in Menlo Park, CA
    Anonymous Interview Candidate in Menlo Park, CA
    Application Details

    I applied online. The process took 2+ weeksinterviewed at Facebook in September 2013.

    Interview Details

    Applied online and got an email the next day from an HR staff member.

    1) Screening call with HR staff - just asking about my work experience and motivation for applying. Straightforward. The HR person gave me some information about the position, and plenty of information about how to prepare for the later interviews (below).

    2) Preliminary interview (can choose to either do on-site 1:1 or phone with online shared-document for coding). I went on-site. My interviewer asked a series of basic stats questions (if X1 and X2 are normally distributed (and IID) with mu, sigma, and Y=X1+X2, what is the mean and s-dev of Y?). Then basic binomial stats question - I got a little tripped up due to the nervousness, but it wasn't bad. Then he asked me to conceptually explain how I'd check if two numbers in an array sum to X. Then asked for the algorithm's time-complexity, and then asked if I could do better. Eventually he asked me to code up the faster version on the white-board. He said that he was recommending that I come for the on-site interview despite my having a bit of difficulty here and there. Nice of him to give me the benefit of the doubt. And he gave me more details about the final interview process...

    At this point I got passed from the screening HR person to another one, and at the same time I got another job offer so I asked to accelerate the process. They were very accommodating, which was really nice. Final interview was scheduled for 3 business days later and I was told I'd know if I was going to receive an offer the same day as my final interview! About as quick a turn-around as I can imagine them doing. Very helpful.

    3) Final on-site interview consists of 5 quick meetings (30min each) with different analytics team members and one Product Manager. Was coding on the white-board in 3/5 of the interviews. First one was dynamic/recursive programming focused (Python). Second one was database insight focused (SQL) that began with a description of a SQL table and a new feature and then asking what metrics you'd look at to diagnose the health of the feature/product. Then write those queries. He told me what numbers I would have seen from those queries, and then asked me what that would imply to me, and then he had me do another few queries to diagnose what might be giving the skewed numbers he'd given me. Third one started with a straight-forward Bayesian stats question (I realized it was most amenable to the Bayesian approach after flailing with frequentist stuff for a minute), then we moved to a few questions about Recommendation systems and any intuition I had around those. Fourth one started with an explanation of a "new feature" and a graph of adoption rates, then asked me to explain to a non-technical person what the graph meant/implied. Asked for any ideas I had around why the graph might be shaped the way it was. Last one was with a Product Manager who asked what products I was interested in - a few probing questions to make sure I'd done some homework on those products. Then some A/B testing questions where he explained another change they'd made to one of their products and asked me how I'd decide if that was a good change or not. Then some questions about how I'd diagnose why something wasn't working as expected.

    I felt like I did well - but I didn't nail the questions right away. I got the answers, but I'd bet that I flailed a bit too much on-route for the interviewers' tastes. Sort of a shame since I see a little bit of flailing around as an important part of the creative problem-solving process, but I could understand how it wouldn't inspire confidence in someone who already knows the answer and is just waiting for you to get there. And maybe they just want people who know all the answers already or never get challenged by anything.

    In any case, the whole experience was very professionally handled. I was very impressed by the transparency of their process. I had seen the Glassdoor interview feedback from a few unhappy previous interviewees and it was clear that (at least in my case) the HR team had seen the same complaints and had corrected things as much as they could. I was impressed - definitely a good interview experience.

    Interview Questions
    • You're about to get on a plane to Seattle. You want to know if you should bring an umbrella. You call 3 random friends of yours who live there and ask each independently if it's raining. Each of your friends has a 2/3 chance of telling you the truth and a 1/3 chance of messing with you by lying. All 3 friends tell you that "Yes" it is raining. What is the probability that it's actually raining in Seattle?   View Answers (20)
    No Offer
    Positive Experience
    Difficult Interview
  6.  

    Data Scientist Interview

    Anonymous Interview Candidate in Menlo Park, CA
    Anonymous Interview Candidate in Menlo Park, CA
    Application Details

    I applied through a recruiter. The process took 2+ monthsinterviewed at Facebook in February 2014.

    Interview Details

    Facebook reached out to me via... a facebook message. I wasn't actively looking, but decided to go through the interview process because why not? Maybe they could offer me something my current employer couldn't. The interview process started with two phone interviews. The first was just information and some fact checking. The second was a bit more technical and I had to show the ability to code and answer statistical questions online as one (or more) people watched me type. Then they flew me out for a day/night and I went through 5 interviews in a row (30 minutes each). Facebook has a beautiful Menlo Park campus. Throughout the interviews, only one simple bayesian stats question was asked. Everything else was business questions and computer science questions. I think my training is much more stats/machine learning oriented, so I struggled with a few questions. I signed a NDA, so I can't disclose the exact questions. They asked me on optimal algorithms, standard SQL coding, and business problems. It was very interesting and they did a good job letting me work through things on my own. I think they were looking for someone with more computer science/programming experience than I had.

    Interview Questions
    • Again, I can't talk about the specific question, but after I wrote up a simple algorithm, the interviewer asked me for a more efficient solution. I really struggled with that.   Answer Question
    No Offer
    Positive Experience
    Difficult Interview
  7.  

    Data Scientist Interview

    Anonymous Interview Candidate
    Anonymous Interview Candidate
    Application Details

    I applied through a recruiter – interviewed at Facebook in September 2014.

    Interview Details

    I was contacted by a recruiter and she set up a technical interview for me. But the interviewer was late for about 15 minutes for the phone interview. Then we rushed to coding questions. He gave me some question and asked me to code. I would say these coding question looked simply but it is difficult to get them right without bugs in one time.

    Interview Questions
    • I would say the question was expected but there were tricks. It would not be easy to get them right in one time under the interview setting.   Answer Question
    No Offer
    Neutral Experience
    Difficult Interview
  8.  

    Data Scientist Interview

    Anonymous Interview Candidate
    Anonymous Interview Candidate
    Interview Details

    Was contacted through email and then had our initial phone call. After that, the interviewing process became a total mess. The recruiter frequently did not respond for days, handed me off to another recruiter, and scheduled interview times which I explicitly said were not possible for me. I understand they are busy during recruiting season but this showed a lack of care for the candidate in my opinion.

    Interview Questions
    • I got tripped up by a question on probability and game theory during my second phone interview.   Answer Question
    No Offer
    Average Interview
  9. 5 people found this helpful  

    Data Scientist Interview

    Anonymous Interview Candidate in Menlo Park, CA
    Anonymous Interview Candidate in Menlo Park, CA
    Application Details

    I applied through a recruiter. The process took 2+ monthsinterviewed at Facebook in July 2014.

    Interview Details

    Facebook has two data science teams, the "core" team (which is the one featured in various news stories), and the product/growth team. I interviewed for the product side, so a core data science interview might be substantially different. From my experience, I get the sense that "data scientist" on the product side is a misnomer, and they are more of the business analysts; while the "core" team is similar to other data science teams in the bay area.

    The first interview is a phone screen (or on-site if you're local). They asked a few SQL and probability questions, and it was over in ~30 minutes. My interviewer was friendly and enthusiastic, and the questions weren't particularly difficult.

    The second interview was on-site, and involved talking with 5 different people (or groups of people). Each interviewer had a specific task they were asking about, including business analytics/product health questions, stats/probability theory, algorithms, and more SQL. The questions weren't particularly hard or out of left field but they're looking for you to answer confidently and efficiently.

    The people were overwhelmingly friendly and tended to be enthusiastic about working for Facebook (although, at least 2 of my interviewers subtly admitted they were casually looking for jobs - so, I suspect even employees at Facebook aren't 100% fulfilled by their positions).

    Interview Questions
    • I was surprised that there were no machine learning or data mining questions, or any personality/experience ("tell me about a time when you...") questions. The more technical questions were things that a graduating CS student would succeed at, but did not involve principles that you would actually use in practice in a data role at a company.

      Also, make sure you continue working on a problem until you've provided the most efficient solution you think you can. I stopped after I had a working solution, and indicated to the interviewer that I don't think it's the most efficient solution. The interviewer said it was fine and we moved on to another question. Nonetheless, the biggest piece of feedback I got from the recruiter afterwards is that I didn't provide a solution that was sufficiently efficient.
        Answer Question
    No Offer
    Neutral Experience
    Average Interview
  10.  

    Data Scientist Interview

    Anonymous Interview Candidate in Menlo Park, CA
    Anonymous Interview Candidate in Menlo Park, CA
    Application Details

    I applied through a recruiter. The process took a dayinterviewed at Facebook in March 2014.

    Interview Details

    I was first contacted by a sourcer for a different position, but the recruiter that she connected me to never replied my email. A few months passed, I received an offer from another company so I thought I'd check in with the recruiter again. He emailed back, but ultimately the position he was recruiting for wasn't a good fit. He passed me to a second recruiter, who's super efficient in terms of both scheduling and getting back to me with the results. It took him literally less than 24 hours from the beginning of my interview to get me a verbal offer. Super impressive.

    For the onsite, there were 5 back-to-back 30-min interviews. It was quite intense, and a lot of talking. They should've fit a 5 min break here and there, but oh well. There's a few algorithm questions, stats, design, research background, etc.

    Interview Questions
    • It was all a blur to me now. I don't think there was anything too difficult in particular, but lots of talking and have to focus since all interviews were back-to-back.   Answer Question
    Reasons for Declining

    It was a very tough decision. Honestly, could've gone either way. Facebook's offer was a tad bit higher, but I thought I'd give the other company a shot for now.

    Declined Offer
    Positive Experience
    Average Interview

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