…[compared to the United States] income plays a larger role in buffering children’s health from the
effects of chronic conditions in England. We find no evidence that the
British National Health Service, with its focus on free services and
equal access, prevents the association between health and income from
becoming more pronounced as children grow older.
Here is the paper. Of course equity is not the only argument for single payer systems. Here is part I of the series, concerning Canada and the (possible) continuation of the health-income gradient there. Many of you were skeptical about the reported result, but here is further evidence. Most of all, the determinants of health are not well understood; that is itself a sobering fact no matter what your policy point of view.