Facebook
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Facebook Data Scientist Interview Questions & Reviews

Updated Apr 13, 2014
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Positive Experience

Difficult Interview

Data Scientist Interview

Data Scientist
Menlo Park, CA

I applied through a recruiter and the process took 2 months - interviewed 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 Question – 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

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Declined Offer

Positive Experience

Average Interview

Data Scientist Interview

Data Scientist
Menlo Park, CA

I applied through a recruiter and the process took a day - interviewed 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 Question – 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

Reason 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.

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3 people found this helpful

Declined Offer

Neutral Experience

Easy Interview

Data Scientist Interview

Data Scientist
Mountain View, CA

I applied through an employee referral and the process took 3 months - interviewed at Facebook in January 2014.

Interview Details – My resume was entered into the system by a friend who currently works there, but after a week and no contact, I applied online to a Data Scientist position.

Data scientists at Facebook have a totally separate hiring process from software engineers.

You have an initial phone screen by a data scientist which will focus on your 'analytical ability.' For those of you who (like me) have no idea what that means, it means a tiny bit of coding/scripting in a language of your choice while you work a reasonable, made-up data science scenario. They'll give you pretend access to a pretend database of information, have you write a few queries, give you fake data for your output, and have you debug plausible scenarios for that fake data.

I received word rather quickly (two days later) that I passed the phone screen and would be invited to Mountain View for a day of interviews. I scheduled those interviews for 3 weeks down the line.

Interviews at Mountain View are grueling, not because of their technical difficulty, but rather because of the interview setup. I was interviewed in a tiny closed cubicle no more than 8 feet x 8 feet; room for two one-seater couches and a tiny table. The wall was a whiteboard. There were 5 back to back 30 minute interviews, and while the interviewers were apparently supposed to ask if I needed water or a bathroom break, they often forgot to do so. The next interviewer was waiting right outside when the last interview ended. After we covered all of the technical content (about which I signed an NDA, so I unfortunately will not share the details of that), I had about 120 seconds to quiz my interviewer about what data science is like at Facebook.

I may have earned brownie points with one on-site interviewer for stopping him when he started asking me the same question that I had had during my phone screen. He thanked me and changed to a new problem.

I studied for the Data Scientist interviews by:
a) coding in python (which I do for my job; they were happy to let me code in python for the on-site interviews)
b) reviewing Stanford's online statistics 101 class
c) doing a few 'hat trick' type probability puzzles

I was well prepared for their interview questions.

I heard back from my recruiter 1 week after on-site interviews and received a generous offer with a fungible 2-week acceptance deadline.

Reason for Declining – Ultimately, I felt that most of the data scientist projects (which I admittedly did not hear very much about) at Facebook were either in their infancy or related to ads. I think Facebook will be an incredible place to be a data scientist at in 2 years, but at the moment, there is more exciting work to be done elsewhere.

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3 people found this helpful

Accepted Offer

Positive Experience

Data Scientist Interview

Data Scientist
Menlo Park, CA

I applied through an employee referral and the process took 3 months - interviewed at Facebook in September 2013.

Interview Details – This was a very long process. However the recruitment team was extremely helpful in keeping me completely informed at every step of the way (a huge plus).

As a disclaimer, coming from years of working in academic settings I have no point of comparison. These are just my personal impressions.

I was introduced to a recruiter after one of our students started working at Facebook. He was very prompt in getting back to me and setting up a phone call. He then passed my resume to another recruiter (closer to my area of expertise).

Over the next few weeks, I had a number of phone conversations with different people (mostly analytic, coding and statistics type questions.) The recruiter working with me was very prompt in touching base with me after each interview, telling me how they felt about the interview and getting my feedback on how I felt about it. After a few weeks they flew me to Menlo Park for an on site interview.

The on site interview consisted of a series of five 30-minute interviews with project managers, data scientists and software engineers, all of whom were very engaging and interesting people. Talks were 1/4 about my current work, a bit less than 3/4 technical questions they expected me to work through, and a few minutes of time for my questions about the company, its people and processes.

The recruiter reached out to me after the on site interview and scheduled two more phone interview, and an offer was made shortly after the last phone interview.

Interview Question – Nothing unexpected, mostly because they will tell you in detail what to expect in each interview. Coding on a collaborative text editor while doing a phone interview was new to me. I had a lot of typos, and syntax errors the first time I tried it. I'd recommend doing a practice run with a friend just so one gets used to the set up.   Answer Question

Negotiation Details – No real negotiations. The offer was very good, and they had wooed me completely with the conduct of their employees.

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11 people found this helpful

No Offer

Positive Experience

Difficult Interview

Data Scientist Interview

Data Scientist
Menlo Park, CA

I applied online and the process took 2+ weeks - interviewed 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 Question – 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 (18)

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7 people found this helpful

Accepted Offer

Positive Experience

Difficult Interview

Data Scientist Interview

Data Scientist
Menlo Park, CA

I applied online and the process took 3 weeks - interviewed 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 Question – 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.

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No Offer

Neutral Experience

Data Scientist Interview

Data Scientist

I applied online and the process took 2 weeks - interviewed at Facebook.

Interview Details – I heard they were interested in physicists so I applied online and heard from a recruiter within a week. The initial phone interview included a few technical questions but it seemed more like a "cultural fit" screening. They want enthusiasm! We set up an interview on the FB campus a week and a half later. I received an email at 12:30am the morning before my interview with "interview tips". I had no idea what I was getting into and would have needed to study for a few weeks in order to brush up on CS concepts I haven't addressed since undergrad. Went to the interview completely unprepared. As much as they advertise that they want physicists they did not ask any questions, or offer me any time, to ascertain how my experience and skill set may apply to the position. They really just wanted a code jockey. While I have coding experience, it was not sufficient for the position. This is understandable but should have been made clear in the initial screening so as not to waste either parties time. Everyone was nice but very unorganized.

Interview Question – Write C++ code and analyze algorithm complexity. Improve the code.   Answer Question

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No Offer

Negative Experience

Easy Interview

Data Scientist Interview

Data Scientist

I applied online and the process took 2 months - interviewed at Facebook.

Interview Details – The interviewing process was disorganized and unprofessional. i first received an email from a Recruiter from the Product Analysis team. After a screening on the phone, they set me up with a technical interview with a Data Scientist to assess my Python skills.

First, the Data Scientist scheduled didn't show up to my interview. They had a replacemen who I could tell did not want to be there. Aside from cursing in the interview, he was the kind of guy who nitpicked at code that was functionally the same but not the way he would write it. An example would come to mind is using if/else vs. if/elif. At the end of the interview, I have never seen anyone try to get off the phone as fast as him. It ended like "I gotta go" "Ok" "Click."

That ended with a rescheduled phone interview because I wasn't assessed any of my skills. The second phone interview went well, but because I didn't use SQL and insisted on using python they decided i "am a better fit for BI."

Well this is the part of the process that angered me enough to write this review. They transferred me to the BI recruiter who had a screening with me. Keep in mind we are now at 4 phone interviews. He tells me he will set up a phone interview early next week. One week and 2 emails pass by and he is completely missing in action. No response to any way I try to contact him.

 If I have one pet peeve with Recruiters is when they lie to and/or ignore candidates. In my experience with Facebook, I had both.

Interview Question – The questions mostly revolve around manipulation of data in SQL/Python but are basic. I wish I had something more specific.   Answer Question

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No Offer

Positive Experience

Difficult Interview

Data Scientist Interview

Data Scientist
Menlo Park, CA

I applied through an employee referral and the process took 5 weeks - interviewed 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 Question – What would you add to Facebook and how would you pitch it and measure its success.   Answer Question

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No Offer

Neutral Experience

Data Scientist Interview

Data Scientist

Interviewed at Facebook

Interview Details – First a conversation with a recruiter, then 2 short on-site interviews. The final onsite was with 5 interviewers, one of them product manager.

Interview Question – Fairly involved SQL questions involving joins.   Answer Question

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