Longitudinal research designs and utility in the Asian and Pacific region.

Longitudinal research which includes panel research is the term used to differentiate the methodology and utility of prospective studies from that of cross-sectional research. It describes not a single method but a family of methods that measure change by linking individual data across time. In this article the authors provide an overview of longitudinal research design and utility in the Asian and Pacific region which is partly based on the articles presented at the International Conference on Understanding Health and Population over time which was organized in Bangkok on 24 and 25 May 2007 by the Institute for Population and Social Research.