CHAPTER 3
Measuring Personality
FROM CONCEPTS TO DATA
The whole trick of science is to test ideas against reality , and in order to
do that, something has to be measured. We may suspect that salespeo-ple are likely to be extraverts, but in order to prove it we have to be ableto measure Extraversion and to convince other people that we are mea-suring it successfully . If we can come that far, it is a relatively easy mat-ter to see whether salespeople score higher than others on our measure,although we also have to be concerned with the representativeness ofour sample, the magnitude of the difference we find, and any number ofother problems in interpretation.
In many respects, trait theories of personality are among the easiest
to operationalize (as the process of finding suitable measures for theo -
retical concepts is called). Traits are generalized dispositions, so we
know we must look for evidence of consistent patterns of behavior orreactions across a range of situations. Traits endure over time, so weknow that our measures must give us about the same results when ap -
plied at two different times, say , a few weeks apart. Individuals vary in
the degree to which they can be characterized by a trait, so we know ourmeasure must show a range or distribution of scores.
Based on what we know about the domain, we would be able to
measure Extraversion by getting answers to the following questions:
•How many close friends does this person have?
•How much does this person enjoy parties?
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