Methods for questionnaire design: a taxonomy linking procedures to test goals

Background In the clinical field, the use of questionnaires is ubiquitous, and many different methods for constructing them are available. The reason for using a specific method is usually lacking, and a generally accepted classification of methods is not yet available. To guide test developers and users, this article presents a taxonomy for methods of questionnaire design which links the methods to the goal of a test. Methods The taxonomy assumes that construction methods are directed towards psychometric aspects. Four stages of test construction are distinguished to describe methods: concept analysis, item production, scale construction, and evaluation; the scale construction stage is used for identifying methods. It distinguishes six different methods: the rational method utilizes expert judgments to ensure face validity. The prototypical method uses prototypicality judgments to ensure process validity. In the internal method, item sets are selected that optimize homogeneity. The external method optimizes criterion validity by selecting items that best predict an external criterion. Under the construct method theoretical considerations are used to optimize construct validity. The facet method is aimed at optimizing content validity through a complete representation of the concept domain. Conclusion The taxonomy is comprehensive, constitutes a useful tool for describing procedures used in questionnaire design, and allows for setting up a test construction plan in which the priorities among psychometric aspects are made explicit.