Group interviews come in two primary forms: panel and group. A standard group interview involves one interviewer who interviews many candidates at one time. A group of applicants will come in, and the interviewer will ask them questions all at once. This is most commonly used in high volume hiring processes where more than one person will be employed and are more prevalent in the retail and hospitality industries.
Panel interviews are when there are multiple interviewers meeting with only one job candidate. On the hiring panel are usually the hiring manager, an HR representative, and perhaps a relevant team member.