Psychometrics
Psychometric testing falls into three main types:
Ability tests measure a persons potential, for instance to learn the skills needed for a new job or to cope with the demands of a training course.
Aptitude - there is no widely accepted definition of the difference between ability and aptitude. Most people would agree that to some extent the two terms refer to the same thing: aptitude referring to specific ability, and ability referring to general aptitude.
Personality is a term which is commonly used in everyday language but which has been given a particular technical meaning by psychologists. When we discuss personality we must remember that it is not a single independent mechanism but closely related to other human cognitive and emotional systems.