Research Intern applicants have rated the interview process at Princeton University with 3 out of 5 (where 5 is the highest level of difficulty) and assessed their interview experience as 100% positive. To compare, the company-average is 70% positive. This is according to Glassdoor user ratings.
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The interview was informal with the hiring professor to see if my qualifications matched. There were some technical questions, and being to asked to elaborate on specific prior experiences. Most of the questions were logistical -- we compared expectations, schedules, etc