There is no such consensus in the field of personality measurement as now has been at least partially attained in the field of the measurement of intelligence. One difficulty is that there is no agreement on basic theory. We meet in exaggerated form here the sort of circular problem that bedevils much of psychology and other sciences, that is, theory depends in large part upon observation and measurement, but what is to be observed and measured is determined by theory.
In the field of personality measurement what has happened, apparently, is that the sort of measuring devices that had been useful in intelligence testing were first adapted to "personality" measurement. This type of approach is now exemplified in the personality inventories. From it has developed a rather vague "trait" theory of personality, which has more recently been put on a rigorous basis in Cattell's work. Cattell's tests, however, have not been used in any occupational grouping.
There has also been another line of approach. This is through application of personality theory, particularly analytic theory. Although the Rorschach, the best-known of the projective techniques, was developed in the first place as a technique for studying imagination, many of the later projective techniques such as the Thematic Apperception Test and the Blacky Pictures have had a basis in theory. Even so, relationships between theory and test have been more secondary than primary. There has so far been no attempt to devise tests or to adapt or interpret any of the existing tests in accordance with Maslow's theory of personality development.
Under these circumstances it is impossible to describe pertinent personality variables as easily as intellectual ones, or to discuss their