The quality of any officer selection system needs to be assessed. There are two good reasons for this. Firstly, one needs to know, rather than believe or hope, that the right applicants are selected and assigned to jobs for which they are best suited. This is of paramount importance to the military commanders since the quality of the officer corps is vital for the conduct of military operations which can have dramatic consequences both for the military and their country as illustrated in Norman Dixon’s book On the Psychology of Military Incompetence. Failure to conduct a good professional selection for officers is an unforgivable error. The second reason for the continuous evaluation of the quality of a selection system, is the increasing demand to justify selection decisions made concerning individual applicants or specific groups. In the end, such justification cannot be sustained unless there is verifiable evidence of the predictive validity of the selection system.  One critical decision concerning the quality assessment is the choice of external criteria defining who is a ‘good officer’ and who is performing less well. In many cases, the choice will be a trade-off between relevance, timeliness and measurement quality.