As per my experience, I am giving here a more detailed reply here:
At the SSB the candidate's suitability to be an officer in the Armed Forces of this country is being evaluated through three separate, independent and time tested techniques i.e Psychology, Group testing and Interview.
Suitability in other words is his APTITUDE to lead his men with the Personality Qualities he displays and those he is expected to develop with training. The Personality qualities that they look for are the qualities of an Officer. An officer is a person who is reasonably Intelligent, can communicate his views clearly and justifiably. He should be ready to mix with all strata of people, take responsibility abiding to laid down Rules. He should be able to initiate action with faith in his abilities, convincing others in company without getting unduly perturbed on routine issues. He should be capable of taking calculated risk, have the capacity to work extra hours with an aim to complete his task.

SSB LOOK WHETHER THE CANDIDATE HAVE SOME QUALITIES OR NOT TO BECOME OFFICER IN DEFENCE FORCES BY THEIR VARIOUS TESTS.