Rules Versus Principles in Psychotherapy: Implications of the Quest for Universal Guidelines in the Movement for Empirically Supported Treatments

In this article we briefly review the mission and criteria of the EST movement and several of its criticisms. We question an often-unacknowledged feature of the EST initiative—its foundation in a rule-governed approach to the regulation of psychotherapy—and argue that this approach encounters significant problems that are better resolved through an alternative, principle-based approach. The contrast between these perspectives is illustrated by presenting results of a qualitative research project identifying the implicit principles actually used by expert therapists across psychotherapy orientations to regulate values and interventions within their practice.