When SSI is the only route to health insurance

Re that Nicholas Kristof column alleging skewed incentives in the children's Supplemental Security Income (SSI) program: in a prior post, I looked at a study Kristof cited that does not clearly demonstrate what Kristof implies it does --that an undue proportion of children on SSI transition directly to adult SSI when their eligibility for the children's benefit ends at age 18.

The 2009 study, by Jeffrey Hemmeter, Jacqueline Kauff, and David Wittenberg, does indicate a variety of incentives, some of them potentially perverse, for staying on children's SSI while eligible and for transitioning to adult SSI if possible.  One set of incentives is indeed skewed, thanks to a dearth of resources outside the program.  It's this: SSI, for children and adults alike, can be the only source for health insurance and specific health services: