Content validity of the illness perceptions questionnaire--revised among people with type 2 diabetes: a think-aloud...

to access the cognitions of adults with type 2 diabetes whilst completing items on the Illness Perceptions Questionnaire-Revised (IPQ-R). To determine whether these cognitions are congruent with the meaning of items and subscales as interpreted by researchers and clinicians using the IPQ-R and to identify the nature and extent of problems that individuals experience when completing the IPQ-R.

participants (n = 36) were recruited from a primary care diabetes clinic and a hospital diabetes clinic. They were asked to complete the IPQ-R using a 'think-aloud' methodology.

transcripts were analysed to identify instances where participants expressed problems with item completion, or where there was inconsistency between verbal and written responses.

the most problematic subscales were those of 'personal control' and 'consequences'.

generally, participants found the IPQ-R unproblematic. However, participants had problems with the concept of 'cure' and 'symptoms' in the context of type 2 diabetes, and with the negative phrasing used in some items. These findings have important implications for the interpretation of IPQ-R scores, particularly when the IPQ-R is used as the basis for individualised interventions among people with type 2 diabetes.