Monitoring outcomes in routine practice: defining appropriate measurement criteria.

With the development of an internal market for health care, 'purchasing for outcomes' has become an important if somewhat rhetorical catchphrase. While there is emerging understanding about how it can be pursued, doubts are being expressed over an outcomes rather that a process emphasis. This debate has been confused by a failure to differentiate the role and importance of monitoring outcomes at an individual patient care level from those at an aggregate population/purchaser level. The clinical need to collect outcomes data on individual patient care within routine care settings places additional requirements on measurement development and selection. Traditional measurement criteria, stressing reliability, validity and responsiveness to change, must be supplemented by criteria of feasibility of use, clinical utility and acceptability. One option is to select domains or items of interest from longer instruments initially designed for research, carefully selected in relation to the purposes of measurement. Further measurement criteria must be addressed which stress the relevance of the proposed instrument to the condition and to the participants in the clinical interaction: in particular, patient-centredness and sensitivity to the setting. Monitoring the outcomes of individual patient care within routine clinical practice poses considerable challenges to researchers who are developing instruments and to clinicians who collect and use the data. A shift in emphasis is required towards more context-specific tests, addressing relevance to lay perceptions, to clinical use and to the condition and setting under review. The content validity, the responsiveness to patient-relevant and clinically relevant change and, of course, reliability must have greater primacy. In this way, outcome data which measure the quality of clinical practice and which provide appropriate criteria for research into effectiveness can be generated.