Introduction to the special section on process models in psychological assessment

This article provides a basic description of stochastic process models and their applicability to problems in assessment psychology. Such models accom modate inevitable uncertainty in prediction, hence their designation as sto chastic. They also formally incorporate the variable of time. The dynamic a spects of the models are examined, in terms of the specific time, and time- related variables they accommodate. Distinctions are made between continuou s- and discrete-time models, as well as between parametric and nonparametri c characterization of probability distributions associated with clinically important phenomena. Such phenomena are wide ranging and include remission of florid symptomatology, debilitation in cognitive functioning, clients' r esponding to items on psychometric inventories, and clients' maintenance of therapeutic compliance.