I haven't conducted this personally but it has been conducted in my workplace. This is in a pure BA branch. Generally you will discover the competency level of the BA's, which in turn should help drive training needs for the BA's in the organisation. Analysis of the processes used by the BA's will determine if they are effective and efficient.The assessment may also looks at tools in the toolkit available to the organisation and assess whether they are appropriate. The person conducting the assessment ideally would be experienced, ideally having analysed similar organisations so that your organisation can be benchmarked against them, obvioously from the asessors opinion.