Predicting the on-the-job behavior of a job candidate simply from an interview or two based upon interviewing skills training best practices can be problematic.
All your questions were answered satisfactorily, the resume lists more-than-adequate experience in relevant roles, and references have been positive. But still…can you guarantee the interviewee will be able to work well in your unique environment, get along with your team and deliver the results you need? One way to find out is to assign a real-world project.
The advantages to the company are many. Assuming the candidate wants the job, they will give it their best effort. Some organizations even assign projects to several potential hires in order to compare the results and offer the job to the superior candidate. The work gets accomplished with a minimum of expense or risk on your part.
As well, the candidate will have had an opportunity to work with your team. When they come aboard, they will have a jump start on the work ahead.