A former colleague referred me to the Data Scientist position at TikTok, which kicked off the interview process. The technical screen included a question about designing an A/B test for a ranking model, followed by an SQL challenge related to user sessions. The funny part was that the SQL problem was a twist on one I had been grinding through on PracHub just a few days prior. After some behavioral interviews, I received an offer, but ultimately decided to decline as it didn't align with my goals.
Interview questions [2]
Question 1
Walk me through how you'd design an A/B test for a new ranking model on the For You feed, and how you'd pick guardrail metrics.
Given a sessions table (user_id, session_start, session_end, country), write SQL to find the users whose average session length grew the most week-over-week.
I applied online. I interviewed at TikTok (London, England)
Interview
one medium level sql test and an open question
Since i'm not familiar with business context(though i actually spent time preparing AB test and causal inference), i didn't get what i should answer.
Interview questions [1]
Question 1
if tiktok shop is going to launch in Netherland, how to evaluate it before AB test
