Challenges in measuring patient outcomes.

Reliable and valid measurement of outcomes is a key criterion for assessing the efficacy and effectiveness of nursing interventions. However, measurement in outcomes studies present a special challenge due to the longitudinal nature of such studies as well as the need to operationalize the intervention, specify and select the most relevant contextual and outcome variables, and delineate the influence of other providers on outcomes. This article specifies measurement-related issues and problems that threaten the credibility of outcome studies. Client-related and instrument-related measurement issues which could compromise outcomes measurement are also addressed.