Does selective migration cause the increasing socio-economic gradient in ill-health?
[Project number 30036] The current method of assessing whether inequalities in health within populations may be changing is to compare the health status of areas, or groups of areas, over time. However, this methodology ignores the potential impact of migration and especially selective migration. Selective migration may be the cause of increasing inequalities between areas even if the health of the individuals within these areas have not changed. In order for this to occur there would have to be a net movement of healthier people from deprived areas or a net movement of less healthy people to deprived areas. Furthermore there must be no significant gradient constraint; that is people moving from more to less deprived areas must have a level of health approximately equal to or better than the group they are joining. The evidence relating to selective migration is mixed, though one important factor appears to be the level of analysis, with studies looking at a local geographical level mo
