Social scientists frequently refer to the 'greying' of the population in the west, the extension of the average lifespan to around the age of 76, and the projected increases in the numbers of people aged 85 and over, with the ensuing problems of chronic illness and disability that often accompany very old age. Increasing interest is being expressed in positive aspects of ageing: given the increases in life expectancy during this century, is it resulting in a life worth living? Concern is heightened by the estimate that, although most people aged 65+ live in their own homes and are relatively healthy and independent, years of disability can begin as early as 60 years. Conversely, some researchers and policy makers feel that enough time has been spent on the negative aspects of ageing and that the balance should be addressed by analysing successful, or positive ageing (sometimes defined in terms of an overlapping but separate dimension 'health-related quality of life'), with the aim of promoting well-being for future generations.