Double Dutch: the 'think-aloud' Brief IPQ study uses a Dutch translation with confusing wording and the wrong instructions.

This commentary describes the methodological shortcomings and the misleading presentation of the 'think-aloud' Brief Illness Perception Questionnaire (IPQ) paper by van Oort, Schröder, & French (2011). We highlight that this paper uses a confusing Dutch translation of the scale, fabricates incorrect instructions, and employs a sample in which the majority of patients do not have established illness diagnoses. We believe these problematic methodological issues are the likely cause of the results presented in the paper. We argue that the conclusions of the paper are inaccurate, unsupported, and overstated given the limitations of the study. Furthermore, the think-aloud method cannot be a substitute for the established psychometric methods for assessing reliability and validity. ©2011 The British Psychological Society.