Moreover, they most likely affect some very specific groups of the population rather than the aggregate. Given the correlation between health indicators or the share of the inactive population declaring too sick or disabled to work and disability recipients, they cannot be included simultaneously in the regressions. The main issue remains that once on disability benefits or sick the likelihood to re-enter the labour force is limited. But it may also just reflect the fact that inactive people have lower income, hence live in more crowded houses or in cheaper areas far away from job centres.