He argued that that is was necessary to look at a much larger number of traits in order to get a complete picture of someone’s personality.
Whereas Eysenck based his theory based on the responses of hospitalized servicemen, Cattell collected data from a range of people through three different sources of data.
- L-data – this is life record data such as school grades, absence from work, etc.
- Q-data – this was a questionnaire designed to rate an individual’s personality (known as the 16PF) .
- T-data – this is data from objective tests designed to ‘tap’ into a personality construct.
Cattell analyzed the T-data and Q-data using a mathematical technique called factor analysis to look at which types of behavior tended to be grouped together in the same people. He identified 16 personality traits / factors common to all people.
Cattell made a distinction between source and surface traits. Surface traits are very obvious and can be easily identified by other people, whereas source traits are less visible to other people and appear to underlie several different aspects of behavior.
Cattell regarded source traits are more important in describing personality than surface traits.
Cattell produced a personality test similar to the EPI that measured each of the sixteen traits. The 16PF (16 Personality Factors Test) has 160 questions in total, ten questions relating to each personality factor.