Principal Investigator(s): Finkelstein, Amy, Massachusetts Institute of Technology and National Bureau of Economic Research; Baicker, Katherine, Harvard University and National Bureau of Economic Research
In 2008, a group of uninsured low-income adults in Oregon was selected by lottery to be given the chance to apply for Medicaid. This lottery provides an opportunity to gauge the effects of expanding access to public health insurance on the health care use, financial strain, and health of low-income adults using a randomized controlled design. The Oregon Health Insurance Experiment follows and compares those selected in the lottery (treatment group) with those not selected (control group). The data collected and provided here include data from three surveys and administrative records on Medicaid enrollment, the initial lottery sign-up list, welfare benefits, and mortality.
This data collection has five data files:
Dataset 1 (Descriptive Variables) contains administrative data on the lottery from the state of Oregon: demographic characteristics that were recorded when individuals signed up for the lottery, date of lottery draw, and information on who was selected for the lottery, applied for the lotteried Medicaid plan if selected, and whose application for the lotteried plan was approved. Also included are Oregon mortality data for 2008 and 2009.
Dataset 2 (State Program Variables) contains information from the state of Oregon on the individuals' participation in state programs: Medicaid, Supplemental Nutrition Assistance Program (SNAP), and Temporary Assistance to Needy Families (TANF).
Datasets 3-5 contain the data from the initial, six month, and 12 month mail surveys, respectively. Topics covered by the surveys include demographic characteristics; health insurance and access to health care; health care needs, experiences, and costs; overall health status and changes in health; and depression and medical conditions and use of medications to treat them.
The collection also includes a ZIP archive which contains analysis replication code: SAS programs that were used to produce analyses reported by the principal investigators.
One or more files in this study are not available for download due to special restrictions ; consult the restrictions note to learn more. You can apply online for access to the data. A login is required to apply for access.
As explained in the ICPSR Processing Notes in the codebook, many variables are restricted from general dissemination for reasons of confidentiality. Users interested in obtaining the restricted variables must complete an Agreement for the Use of Confidential Data, specify the reasons for the request, and obtain IRB approval or notice of exemption for their research. Apply for access to the restricted data through the ICPSR restricted data contract portal.
WARNING: This study is over 150MB in size and may take several minutes to download on a typical internet connection.
Finkelstein, Amy, and Katherine Baicker. Oregon Health Insurance Experiment, 2008-2010. ICPSR34314-v1. Ann Arbor, MI: Inter-university Consortium for Political and Social Research [distributor], 2013-12-02. doi:10.3886/ICPSR34314.v1
Persistent URL: http://doi.org/10.3886/ICPSR34314.v1
This study was funded by:
- Robert Wood Johnson Foundation (64301)
- United States Department of Health and Human Services. Office of the Assistant Secretary for Planning and Evaluation (3P30-AG012810-15S1)
- United States Department of Health and Human Services. National Institutes of Health. National Institute on Aging (P30AG012810, RC2AG036631 and R01AG0345151)
- California HealthCare Foundation (08-1433)
- Smith Richardson Foundation (2008-775)
- Alfred P. Sloan Foundation (6-26-2008)
- John D. and Catherine T. MacArthur Foundation (09-93341-000-HCD)
- United States Social Security Administration (5 RRC 08098400-03-00)
- United States Department of Health and Human Services. Centers for Medicare and Medicaid Services
Scope of Study
Geographic Coverage: Oregon
Date of Collection:
Universe: The individuals registered for Oregon's 2008 Medicaid lottery constitute the study universe. The lotteried health insurance plan, Oregon Health Plan Standard (OHP Standard), is a Medicaid expansion program that covers low-income adults who are not categorically eligible for Medicaid. Specifically, it covers adults ages 19-64 not otherwise eligible for public insurance who are Oregon residents, are United States citizens or legal immigrants, have been without health insurance for six months, have income below the federal poverty level, and have assets below $2,000. From January 28 to February 28, 2008 anyone could be added to the lottery list by telephone, by fax, in person sign-up, by mail, or online. Individuals could register themselves and other adults 19 or older in their household.
Data Types: administrative records data, experimental data, survey data
Data Collection Notes:
A detailed description of this study is provided in:
Finkelstein, Amy, Sarah Taubman, Bill Wright, Mira Bernstein, Jonathan Gruber, Joseph P. Newhouse, Heidi Allen, Katherine Baicker, and the Oregon Health Study Group. The Oregon Health Insurance Experiment: Evidence from the first year. The Quarterly Journal of Economics 127, (3), 1057-1106.
The Oregon Health Insurance Experiment also collected hospital discharge and credit report data which were not provided to ICPSR.
Sample: The original lottery list provided by the state contained 100,600 records of persons who signed up for the lottery. The study group pared down this list to 74,922 individuals by removing duplicate and deactivated records; individuals who were not eligible for the lotteried program because they were too old, too young, or gave an address outside of Oregon; individuals who lived at institutional addresses or who were signed up by an unrelated third party; individuals with multiple active records on the lottery list; and those who died prior to the lottery notification date. The data files in this collection only cover these 74,922 individuals, of which 29,834 were selected by the lottery. Both the initial and 12 month mail surveys were administered to the same 29,589 treatment and 28,816 control cases. The six month survey was limited to a subsample of these cases: 5,312 treatment and 7,712 control cases. The initial survey respondents could respond my mail and phone, the six month respondents by mail only, and the 12 month respondents by mail, phone, and Web.
Mode of Data Collection: mail questionnaire, telephone interview, web-based survey
Response Rates: The response rates were 45 percent for the initial survey, 49 percent for the six month survey, and 41 percent for the 12 month survey.
Extent of Processing: ICPSR data undergo a confidentiality review and are altered when necessary to limit the risk of disclosure. ICPSR also routinely creates ready-to-go data files along with setups in the major statistical software formats as well as standard codebooks to accompany the data. In addition to these procedures, ICPSR performed the following processing steps for this data collection:
- Checked for undocumented or out-of-range codes.
Original ICPSR Release: 2013-12-02
- 2013-12-05 ICPSR added a list of the Oregon Health Insurance Experiment grants to the codebook.
Related Publications (?)
- Citations exports are provided above.
Export Study-level metadata (does not include variable-level metadata)
If you're looking for collection-level metadata rather than an individual metadata record, please visit our Metadata Records page.