The personality psychologist Theodore Millon strove to articulate a comprehensive personality measurement system, distinguishing between functional and structural domains. The functional domains consist o expressive acts, interpersonal conduct, cognitive style and regulatory mechanisms. The structural domains consist solely of objective representations, self-image, morphologic organization and mood/temperament. These domains are similarly organized under specific categories.

The behavioral level consists of the functional domains o expressive acts and interpersonal conduct. The phenomenological level consists of the functional domain o cognitive style and the structural domains of object representations and self-image. The intrapsychic level consists o the functional domain of the regulatory mechanism and the structural domain of morphologic organization. Finally, the biophysical level consists solely of mood/temperament.

This theoretical framework functions as an answer to the question of content validity of the assessment. This is itself a measure of what is actually being assessed in personality measurement, and how to assess it. This causes a great deal of internal strife among personality psychologists. Theodore Millon wants to provide a comprehensive account of the human personality rather than conceiving of personality strictly in terms of biology, psychodynamics, or some other theoretical framework, as this would be reductionistic. In the words of Millon:

"The integrative perspective encouraged here views personality as multidetermined and multireferential construct that may be profitably studied and assessed across a variety of content areas. The term "multireferential" is an important one for assessment purposes."

The next article will consist of a more comprehensive look at the functional aspect of Theodore Millon's personality psychology. This will include the expressive acts, interpersonal conduct, cognitive style and regulative mechanism of the individual's personality.