Cognitive Interviews: Recommendations for Best Practices in Clinical Outcome Assessment (COA) Measure Development and Validation.

Cognitive interviewing is a technique that can be used to improve and refine questionnaire items. Cognitive interviewing is now a commonly used method to improve the reliability and validity of clinical outcome assessment instruments by identifying problems respondents have in understanding and answering the draft questionnaire items, and then to revise the items to improve understanding and response accuracy. Although practitioners are in general agreement regarding the basic principles and aims of the cognitive interview, there is considerable variation in practitioners' approaches. The aim of this paper is to put forward a few recommendations regarding best practice in the application of cognitive interviews as part of the developmental process of clinical outcome assessment instruments. The paper is structured in order that each section addresses a discrete and key element of the cognitive interview process that ranges from selecting the appropriate methodology, development of the interview guide, interviewer recruitment and training, and determining sample size through to approaches for analysis and writing the cognitive interview report. Each element of the cognitive interview process is divided into (1) the rational underpinning the methodology; (2) the recommended procedural steps; and (3) an overview of lessons learnt from previous research.