The creation of the diagnostic accuracy quality scale (DAQS)

Background: The utility of a dedicated clinical test is dependent on the diagnostic accuracy values and the quality of the study in which the test was examined. Scales allow a summative scoring of bias within a study. At present, there are no scales advocated to measure the bias of diagnostic accuracy studies. Objective: The objective of this study was to create a new diagnostic accuracy quality scale (DAQS) that provides a quantitative summary of the methodological quality of studies evaluating clinical tests and measures. Design: The study used a four-round Delphi survey designed to create, revise, and develop consensus for a quality scale. Methods: The four-round Delphi involved a work team and a respondent group of experts. An initial round among the work team created a working document, which was then modified and revised, with opportunities to create new items threaded in the second round. Rounds III and IV involved voting on the importance of each of the proposed items and consensus development from the respondent group. Consensus for the selection of an item required a 75% approval for the importance of that item. Results: Sixteen individuals with a variety of research/professional backgrounds made up the respondent group. Modification and revision of the initial work team instrument created a scale with 21 items that reflected potential areas of methodological bias. Limitations: The new scale needs validation through weighted assessment. In addition, there was a large proportion of physical therapist/researchers on the work team and the respondent group. Conclusions: Systematic reviews allow summation of evidence for clinical tests and scales are essential to critique the quality of the articles included in the review. The DAQS may serve this role for diagnostic accuracy studies.