Tailor-made single-item measures of doubly concrete constructs
Lars Bergkvist and John Rossiter
Multiple-item measures of all constructs have been the norm in academic marketing research, including research on advertising, for the last 30 years. Recent research challenges this norm on theoretical grounds for not being applicable to all types of constructs of interest in the social sciences (Rossiter 2002) as well as on empirical grounds (Drolet & Morrison 2001; Bergkvist & Rossiter 2007). Specifically, Rossiter (2002) argues that single-item measures provide valid measurement of ‘doubly concrete’ constructs - that is, constructs for which both the object of measurement and the attribute of measurement are clear and unambiguous for those rating the object on the attribute. Bergkvist and Rossiter (2007) show that this argument holds empirically by demonstrating that the predictive validity of single-item measures of the doubly concrete constructs attitude towards the ad (AAd) and brand attitude (ABrand) is equal to the predictive validity of multiple-item measures of the same constructs. Moreover, Drolet and Morrison (2001) demonstrate mathematically that increasing the number of items in a measure of a doubly concrete construct (in their study, AAd) will actually decrease its validity compared with a measure with one, or at most two, good items, although they did not test this relationship empirically. The multiple items were attempted synonyms of the attribute descriptor, which is the typical way of generating multiple-item measures of doubly concrete constructs.