Measuring bias against disconfirmatory evidence: An evaluation of BADE task scoring methods and the case for a novel method

Research suggests that bias against disconfirmatory evidence (BADE) may help maintain delusions in the face of overwhelming evidence against them. Much of this research has employed Woodward and colleagues’ BADE task. Different methods of scoring this task, many of which have significant drawbacks, are currently used by researchers, making it difficult to compare results across studies of BADE. Continued advancement of BADE research demands a scoring method with more favorable psychometric properties that is used more consistently by researchers. Here, we take a data-driven but theory-informed approach to the development of a new method for scoring the BADE task. This new scoring procedure is more parsimonious than previous metrics of BADE but captures the vast majority of their predictive variance in relation to delusions. This new method may therefore be capable of inspiring consensus use among BADE researchers. If so, it could significantly increase the ease of comparing future studies of BADE.