Editorial Comment:

The Department of Health (DoH; 1996) Strategic Review of Psychotherapy identified the need for practitioners to use similar outcome measures as part of the framework of clinical effectiveness. This paper presents the rationale for developing and implementing a core outcome battery in routine clinical practice as well as psychotherapy research. A core battery is defined as a set of measures that are applicable to all patients in psychotherapy, regardless of the clinical settings, mode of therapy, or specific problems (clinical population) of the patients. The forces that have determined the current corpus of outcome measures are outlined and contrasted with rational criteria for two levels of outcome batteries: a core battery, and problem-specific batteries. In addition, potential referential measures that act as links between a core and problem-specific outcome batteries are identified. Criteria are set out that a core battery should meet. Emphasis is given to two unique criteria: a collaborative approach to instrument development between researchers and clinicians, and the collection of a subsequent national database. Meeting such suggestions will benefit researchers and clinicians as well as promoting innovation in measurement practice.