However the whole issue of whether a trait exists in all people to a
greater or lesser degree is complicated by different views of the trait
The Idiographic view emphasizes that each person has a unique
psychological structure and that some traits are possessed by only one
person; and that there are times when it is impossible to compare one
person with others. This viewpoint also emphasizes that traits may
differ in importance from person to person (cardinal, central and
secondary traits). It tends to use case studies, bibliographical
information, diaries etc for information gathering.
Most contemporary psychologists tend towards a nomothetic approach (and the trait approach is often viewed solely as a nomothetic approach these days), but they are aware of how a trait may be slightly different from person to person in the way that it is expressed.