Evaluator Effect

The evaluator effect refers to the phenomenon where different accessibility evaluators identify different sets of problems when assessing the same website, leading to variability in evaluation results. This effect has been documented in both expert reviews and user testing, where the evaluator's expertise, interpretation of guidelines, and methodology choices influence which barriers are detected and reported. The evaluator effect is a significant challenge for the reliability of accessibility evaluation and underscores the importance of using multiple evaluators and combining evaluation methods.