Validity of overall self-rated health as an outcome measure in small samples: a pilot study involving a case series

Objective A single-item measure of overall self-rated health (SRH) commonly is used in population surveys, but has not been used in small pilot projects. The purpose of this study was to assess the validity of SRH in small samples. Design We used data from a prospective, observational weight-loss project to compare change in SRH with change in body weight and physical activity (PA) (minutes) over 30 days (n=34). Body mass index at baseline ranged from 25.5 to 50.4 (mean=36.1, median=34.6). SRH was self-assessed using the following question: How would you rate your health overall? Results An increase in weight was associated with a reduction in SRH (r=0.37, P=0.03). An increase in PA was associated with improved SRH (r=0.39, P=0.02). Conclusions A single-item SRH measure may be an efficient method for measuring programme outcomes, and may also be useful for comparing the relative effectiveness of different programmes in pilot projects and quality improvement studies.