The role of deliberate practice in the development of highly effective psychotherapists.

Little empirical research exists about highly effective psychotherapists, and none about the factors that mediate the acquisition and maintenance of superior performance skills (e.g., Ericsson, 1996, 2006; Ericsson, Krampe, & Tesch-Romer, 1993).

Effect size calculations for the clinician: methods and comparability.

Objective: The measurement of clinical change via single-group pre-post effect size has become increasingly common in psychotherapy settings that collect practice-based evidence and engage in feedback-informed treatment. Different methods of calculating effect size for the same sample of clients and the same measure can lead to wide-ranging results, reducing interpretability.

Method: Effect sizes from therapists-including those drawn from a large web-based database of practicing clinicians-were calculated using nine different methods.

The outcome of psychotherapy: yesterday, today, and tomorrow.

In 1963, the first issue of the journal Psychotherapy appeared. Responding to findings reported in a previous publication by Eysenck (1952), Strupp wrote of the "staggering research problems" (p. 2) confronting the field and the necessity of conducting "properly planned an executed experimental studies" to resolve questions about the process and outcome of psychotherapy.