Abstract
Accurate identification and measurement of constructs is particularly relevant to mental health nurses, who often have to work with clients that have intangible needs and problems. In this paper, the measurement of constructs, the relevance of construct validity to nursing research and, in particular, to theory testing will be discussed. Constructs within the health belief model are used to illustrate the discussion and procedure of factor analysis. Analysis of data based on a survey of health beliefs of 276 adults with the chronic condition of insulin-dependent diabetes is presented, interpreted and discussed. Whilst the paper focuses upon specific constructs and study population in order to provide a worked example, the issues raised and principles outlined relate to an analytical model that can be applied to other research problems and settings.