Single measures of deprivation.

STUDY OBJECTIVE A number of measures have been developed which attempt to combine a range of variables into a single, more easily understood dimension of "deprivation". These extend from fairly simple additive measures through to those based on more sophisticated statistical techniques. All attempts to simplify a number of variables into a single, summary measure have limitations. This paper compares a number of more commonly used techniques and discusses their relative strengths and weaknesses. DESIGN Data from the 1991 census is used to show the relative capabilities in discriminating between areas of (a) the Department of Environment's Z score index, a simple additive measure; (b) the Jarman index, not strictly a measure of deprivation but, apart from its importance to health workers, of interest as a weighted index to contrast to simple additive indices; (c) a multivariate technique, namely factor analysis, drawing on the London Research Centre's experience of its use; (d) the index of local conditions, commissioned by Department of the Environment from the University of Manchester. CONCLUSIONS Contrasting these different methodologies highlights relevant considerations in choosing a measure of deprivation, including ways in which the method of construction can dictate how a measure may be used. In particular, simple additive indices should be avoided as they hide too much information and if badly constructed can be meaningless, while weighted indices demand critical use since they tend to lack generality.