Those involved with the criminal justice system have disproportionately high rates of mental illness and substance-use disorders, prompting speculation that health insurance, by improving treatment of these conditions, could reduce crime. This study draws on the 2008 Oregon Health Insurance Experiment to provide new evidence on the impact of Medicaid coverage on criminal justice involvement.
In 2008, the state of Oregon used a random lottery to allocate 10,000 available enrollment spots in one of its Medicaid programs. Lowincome adults selected by the lottery were 25 percentage points more likely to enroll in Medicaid than those who signed up but were not selected. Researchers linked all study participants to individual-level administrative records from the Oregon Judicial Information Network, which includes data on criminal cases, charges, and convictions from 2007 to 2010, providing, to their knowledge, the first experimental evidence on the relationship between Medicaid and crime. They find the following:
• Medicaid coverage has no statistically significant impact on criminal charges or convictions.
• These null effects persist even among high-risk groups, such as individuals with prior criminal records or a history of mental health conditions. This contrasts with earlier quasi-experimental studies, many of which focused on narrower highrisk populations and found reductions in crime. One interpretation is that crimereducing effects of Medicaid for high-risk subgroups may not generalize to the broader Medicaid-eligible population.
These results suggest that the impact of Medicaid coverage on criminal justice involvement may be more limited than previously believed. Importantly, criminal charges and convictions are just one metric for evaluating the benefits of health insurance. Medicaid eligibility and coverage have been linked to a range of positive outcomes, including better access to and increased use of medical care, improved physical and mental health, and enhanced economic security. Nonetheless, for policymakers seeking to reduce criminal behavior specifically, this study suggests that expanding health insurance coverage may not be an effective strategy.