The conventional approach of economists to the measurement of poverty in poor countries is to use measures of income or consumption. This has been challenged by those who favour broader criteria for poverty and its avoidance. These include the fulfilment of 'basic needs', the 'capabilities' to be and to do things of intrinsic worth, and safety from insecurity and vulnerability. This paper asks: to what extent are these different concepts measurable, to what extent are they competing and to what extent complementary, and is it possible for them to be accommodated within an encompassing framework? There are two remarkable gaps in the rapidly growing literature on subjective well-being. First, reflecting the availability of data, there is little research on poor countries. Second, within any country, there is little research on the relationship between well-being and the notion of poverty. This paper attempts to fill these gaps.
Any attempt to define poverty involves a value judgement as to what constitutes a good quality of life or a bad one. We argue that an approach which examines the individual's own perception of well-being is less imperfect, or more quantifiable, or both, as a guide to forming that value judgement than are the other potential approaches. We develop a methodology for using subjective well-being as the criterion for poverty, and illustrate its use by reference to a South African data set containing much socio-economic information on the individual, the household and the community, as well as information on reported well-being. We conclude that it is possible to view subjective well-being as an encompassing concept, which permits us to quantify the relevance and importance of the other approaches and of their component variables. The estimated well-being functions for South Africa contain some variables corresponding to the income approach, some to the basic needs (or physical functioning) approach, some to the relative (or social functioning) approach, and some to the security approach. Thus, our methodology effectively provides weights of the relative importance of these various components of well-being poverty.