Yes, of course the business needs and preference are the two main factors.
But if they do choose to consider the individual candidate in order to place him/her onto a suitable course, it's not just their performance at the interview that's taken into consideration.
You'd be surprised at how much information from personality questionnaires and psychometric testing can be analysed to tell a lot about a particular candidate, and consequently, help indicate where they might be more likely to perform at better levels.
