0.9 Trait theories of personality  (Page 23/41)

L-data deals with the individual’s actual everyday situations. Ideally, L-data can be collected without the need for the judgment of a trained psychometrist. Examples of specific behaviors include things such as their grades in school, the number of automobile accidents a person has had, the number of times they have been arrested by the police, how many organizations they belong to, etc. Sometimes these data are not so easy to obtain, and must be gathered from someone who knows the person well. For example, we may ask friends or family members to rate the person in terms of how sociable they are in school, how emotionally stable they are when playing sports, or how responsible they are (Cattell, 1965).

Q-data is obtained by having the person fill out a questionnaire, such as the information sheet you fill out when waiting to see a doctor for a medical exam. Unfortunately, these data are subject to a number of problems, such as distortions due to poor self-knowledge, delusions about the self, or the deliberate intention to fake the outcome of the questionnaire. Therefore, it is very important that a psychologist choose the right words when developing a questionnaire:

Although a questionnaire looks like a simple series of questions to which a person underlines a brief answer, such as ‘yes’, ‘no’, ‘generally’, [sic] etc., actually a great deal of art enters into the psychologist’s choice of words, the direction of the question, the use of adjectives to ensure that all alternatives are well used, and so on. (pg. 61; Cattell, 1965)

As noted above, T-data is obtained from objective tests. According to Cattell, questionnaire may seem objective, since their scoring is objective, but the process involves having the individual evaluate themselves. In truly objective tests the individual’s specific behaviors or thoughts are directly and precisely measured. It is essential that only closed-ended questions are used, such as multiple choice or Yes-No options. If open-ended questions are used, such as “How do you feel when you wake up in the morning?” it is possible that two psychologists will interpret the answer quite differently. If there is a possibility of different interpretations, obviously the test cannot be objective.

In comparing the three types of data, Cattell made some interesting observations regarding L-data. Although it occurs naturally, measuring it is artificial and somewhat arbitrary. Although it is objective in the sense that it is real behavior, it is neither created nor controlled, it is simply observed. It is also subject to cultural differences much more so than Q-data and T-data. Of particular concern to Cattell, however, was the commonplace nature of L-data:

Much of the irresponsible theorizing on personality criticized in Chapter 1 happens to have grown up in the realm of L-data, for this has been the traditional field of observation of the philosopher, the armchair observer, and the clinician, whereas Q- and T-data have been developed by the psychometrist concerned with the more disciplined methods. L-data is, indeed, the field of behavior that is the common property of everyone…there arises at this point the need for a proper development of measurement techniques particularly as they apply to L-data… (pp. 54-55; Cattell, 1957)