The belief that following rigorous inclusive methods will eliminate bias from ‘quality’ measures ignores the preferences necessarily embedded in any formative instrument. These preferences almost always reflect the interests of its developers when one uses the wide definition of ‘interest’ appropriate in healthcare research and provision. We focus on the International Patient Decision Aid Standards instrument, a popular normative measure of decision aid quality. Drawing on its application to a set of 23 breast cancer screening decision aids, we show the effects of modifications that reflect our own different interest-conflicted preferences. It is emphasised that the only objection is to the implication that any formative instrument should be promoted or treated as the ‘the gold standard’, without a conflict of interests disclaimer, and to the implication that other instruments cannot provide equally valid, high-quality measures.