The interview process was pretty extensive. There were multiple interview rounds.
The first round was a data challenge which tested the candidate's proficiency in using Python or R for data cleaning and preprocessing.
The second round was a phone screen (45 - 60 mints) with a Data Scientist. There were questions about my previous data science related work, basic statistics questions, few questions on software engineering fundamentals, machine learning basics. Overall the difficulty level was moderate. The focus was on checking fundamentals.
The third round was another phone screen (45 - 60 mints) with a Sr. Data Scientist. This round was more technical and mostly the discussion was around machine learning algorithms and their limitations.
Next was onsite at ID's San Diego office. 4 rounds of panel interviews (45 - 60 mints each) with team members and a one-on-one (non-technical) with hiring manager over lunch. All onsite interviews (except with hiring manager) were very technical, focusing on machine learning, programming, statistics, mathematics, map-reduce paradigm, and past work.
Overall my experience was very good. All people I met were very respectful, friendly and courteous. All the interviews were more like discussions rather than typical interrogations. Wherever I got struck I was given hints, which I was able to pick and move ahead.
Tips:
1. Make sure you know everything mentioned on your resume in good detail.
2. Brush up your machine learning and statistics fundamentals.