Decomposition and standardisation of rate differences
by
Valeria Kazakova

Demographers and other scientists have traditionally used the technique of direct standardisation to eliminate compositional effects from the overall rates of some phenomenon in two or more populations. Basically, the technique assumes a particular population as standard and re-computes the overall rates in the populations by replacing their compositions by the composition of the standard population.

Another area of research, namely, the decomposition of the difference between the overall rates in two populations, has been fast developed in recent years. Researchers have attempted to decompose the difference between two indexes (rates, means, proportions, ratios, etc) into the effects of changes in the underlying factors. The technique has been extended to include any number of factors, various functional relationships of the factors with the overall and simultaneous considerations of three or more populations.

This talk is a literature overview of the subject and includes some interesting examples using a classical component analysis. It is shown that the decomposition and standardisation technique makes the net changes in ratios over time more interpretable and understandable.

Date received: October 7, 2001