Can between-session (homework) activities be considered a common factor in psychotherapy?

A common goal for psychotherapies is to enable patients to improve their functioning and reduce distress in the situations and interpersonal contexts in which their problems exist. Although generally associated with behavioral, cognitive, couples, and family therapies, the use of the time between consultation sessions through therapeutic activities is implicit to all psychotherapies. This special series in Journal of Psychotherapy Integration represents an initial effort to make explicit the role of between-session 'homework' assignments in behavioral, client centered, cognitive, experiential, interpersonal, psychodynamic, and systemic approaches. Expert theoreticians, researchers, and practitioners present theoretical and clinical case examples to illustrate homework's role in assisting patient therapeutic progress. We synthesize themes from the issue in a concluding piece in the interests of facilitating future theoretical and empirical work on homework in psychotherapy integration.