I applied in-person. The process took 1 day. I interviewed at Purdue University (West Lafayette, IN) in Sept 2012
Interview
I was enrolled into the PhD program in Materials Engineering department and there was orientation at the very beginning. Professors that were hiring gave talks, and you could talk one on one with the professor of interest. Professors are looking for the the fit of background and your interest in the project. There was a double blind choice to pair the students and professors out of preference.
Interview questions [1]
Question 1
The professor asked me why did I think I would qualify for doing this project?
I applied online. I interviewed at Purdue University (West Lafayette, IN) in Nov 2021
Interview
The interview process is an online presentation of the previous research work. Existing lab members and Professor conduct the interview. It was about giving an overview of the past research projects and skills
I applied through university. The process took 1 week. I interviewed at Purdue University in Mar 2021
Interview
Direct online interview after appealing my interest. I was asked to introduce my research career. So, I presented about 30 mins with detailed technical points. After then, I was accepted.
Interviews occur by phone or not at all. Very different from other universities that have a more strenuous interview/vetting process for students. I think this is a problem with Purdue's graduate student recruitment.