Not everyone who qualifies for health insurance signs up for it. Consider Medicaid, the national health insurance plan for low-income people. Across the U.S., about 14 percent of eligible adults and 7 percent of eligible children are not enrolled in Medicaid. As it happens, when adults do enroll in Medicaid, some of them sign up their eligible children for it, too. This is an example of a “woodwork effect,” as policy analysts have termed it — sometimes, people eligible for social programs may come out of the woodwork, as it…
