Abstract
The authors argue that the Rorschach can and should be used best with a nomothetic foundation that adds an idiographic approach depending on the goal of the assessment. The research supporting this position is reviewed as are conceptual models that are advantageous to this conceptual position. The authors posit that method variance has a powerful impact on the measurement process. Each method is of value in some areas and of limited relevance in others. Self-report measures are most likely to be useful when interest is focused on consciously available and behavioral dimensions of functioning. Depth-oriented, indirect measures such as the Rorschach are most likely to be useful when interest is focused on unconscious, longitudinal, and structural dimensions of functioning. However, to have a full picture of human beings, heteromethod assessment is necessary to capture the full range of functioning and to implement the analytic model of assessment.