This chapter discusses the study design, research methods and research instruments, fieldwork procedures, and data analysis procedures. The study was designed to measure improvement, maintenance or deterioration over time in a cohort of residents, in terms of physical and mental functioning and quality of life. Reliability has been tested in a range of settings using various methods of administration and found to be respectable. The researchers' assessment was recorded using the Spitzer Uniscale. In order to provide a check on the quality of the data produced by the Geriatric Depression Scale (GDS) short screening instruments, a sample of residents was interviewed within six weeks of admission using the Geriatric Mental State Schedule (GMSS). The depression measure was the only principal outcome measure for which precision, rising to fractionally above five per cent of the sample mean, might be significantly adversely affected.