Survey estimates of Medicaid enrollment are 43 percent lower than raw Medicaid program enrollment counts. Why is this the case? Roebuck and Liberman (HSR 2009) find that many people are not reporting that they have Medicaid coverage. “43 percent of Medicaid enrollees answering the CPS as though they were not enrolled and 17 percent reported being uninsured.”
One reason for the underreporting could be that the poor may only enroll after they get sick. Further, if they do not pay for Medicaid, they may feel that they are just receiving government assistance rather than “insurance.”