Dimensions of psychotherapy session impact across sessions and across clients.

The Session Evaluation Questionnaire measures two dimensions of participants' perceptions of psychotherapy sessions, depth and smoothness, and two dimensions of post-session mood, positivity and arousal. In ratings by therapists and in ratings by clients, the same dimensions were identified as underlying variation across sessions and variation across clients. Thus these 'impact' dimensions can be used for session-level comparisons with process variables and for client-level comparisons with outcome variables, possibly permitting two-stage inferences from process to impact to outcome.