The Oregon Experiment--Effects of Medicaid on Clinical Outcomes

Major benefits seen from this Medicaid expansion trial—improved health and well-being; reduced financial strain.

As Medicaid coverage is set to expand in 2014 under provisions of the Affordable Care Act, more Americans will have health insurance. But will that lead to better health and ultimately reduce health care spending?

Oregon state offered an unprecedented opportunity for researchers to study the effects of being enrolled in Medicaid (compared to uninsured) based on data from a randomized controlled trial, the “gold standard” of scientific research.

In 2008 Oregon used a lottery system to select low-income people from the state’s Medicaid waiting list to apply for Medicaid. Using administrative data from hospital discharges, credit reports, and mail surveys, researchers now have evidence of the short-term effects of coverage.

Key Findings:

  • Received needed care. Medicaid coverage increased the use of health care and raised the probability of using outpatient services by about 35 percent; of using prescription drugs by 15 percent; and of hospital admissions by 30 percent. People with Medicaid were 70 percent more likely to report having a regular place of care; and use of preventive care (mammograms up 60%; cholesterol monitoring up 20%).
  • Financial security improved. Medicaid reduced by 40 percent the probability that people had to borrow money or skip paying other bills to cover medical expenses.
  • Self-reported health improved. Medicaid enrollees were 25 percent more likely to report good, very good, or excellent health; 25 percent less likely to screen positive for depression. They are also more likely to report that they are pretty happy or very happy (30%), versus not too happy.


Read more about the Oregon Experiment

What Is the Link Between Having Health Insurance and Enjoying Better Health and Finances?

People with health insurance are much more likely than the uninsured to utilize preventive services and prescription drugs, and they are less likely to incur medical debts.

Read more

Oregon Health Study: A Statewide Study of People's Health and Access to Care

The Oregon Health Study (OHS) examines the effects of health insurance on individuals’ access to and utilization of health care, its effect on family finances, and ultimately its role in improving the health of individuals.

Read more

Read the Health Affairs blog by John Lumpkin.