I didn't have to interview. I applied one month before I received my tentative letter. It took two months for me to officially start. The hiring managers must have based their decision on my resume and credentials alone.

Timed and paneled structured interview using Situational Interview methodolgy, 20 minutes total time including your questions to the panel, Typically 7 questions from 3 panelist. Have to brief and to the point, Limited time for note taking and shuffling papers if your questions are written out.