Interview process involved a phone screen, an 8 hour coding challenge (not a typo) and a google hangouts (video chat) presentation. I was also told there was another in person interview (I am glad I did not make it that far).
The initial interviewer for the phone screen was very nice, open and honest about the process. I was sent a coding challenge within a few hours. Realistically it took ~10 hours, because I really took the time to cleanup, comment and double check my code. The challenge was indicative of the daily duties, which is running linear regression. I was sent an invitation for video chat interview a few days later.
During the video chat, there were three interviewers (One was really cool, one was silent, the other was neither). During the video chat I received zero feedback, zero insight to the company, and honestly zero desire to be a part of the team. Honestly the interviewers did not seem like they wanted to be there and it felt like the interviewers wanted the challenge completed in a particular manner, which could not be known with such an ambiguously worded challenge. An interview is a two way process, but this process felt like a one-way street (that leads to a dead end).
The most frustrating part of the process was being promised feedback more than a week later, which was not given even with a generous buffer period. If a candidate takes time to complete an "8 hour" coding challenge and prepare a presentation; the least you can do is inform them your hiring decision. Not following up with a candidate after they invest that much time shows a lack of organization, respect for candidates, and excellent glimpse of how an employee would be treated.
The moral of the story is if a company requires an "8 hour" data science coding challenge and that company is not revolutionizing the field ( or != Facebook, Amazon, Google, Apple), it is not worth your time.
