This can take anything from a few hours to a few days. Contrary to popular belief, most assessment centres don't require you to camp out in snake-infested woods for a weekend armed only with a map and a packet of dried space food. Although they may seem like a way for assessors to get cheap laughs at your expense by putting you in embarrassing situations, assessment centres are actually used for several very valid reasons. Because they aren't purely interview based, they are less subjective, and don't just cover the same ground in the same way as the first interview. They also allow the employer to find out about your ability to work with others.
Assessment centres are a fairer way to recruit.
You are very close to a job offer. You are competing against the organisation's standards. Be natural and get stuck in. Group exercises Group exercises may involve anything from solving a murder mystery to discussing a given topic or even acting out a job-related scenario. It's the quality of your contributions that's important, not the quantity.