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The Oregon Health Insurance Experiment
Last registered on August 07, 2013

Pre-Trial

Trial Information
General Information
Title
The Oregon Health Insurance Experiment
RCT ID
AEARCTR-0000028
Initial registration date
Not yet registered
Last updated
August 07, 2013 10:25 AM EDT
Location(s)
Primary Investigator
Affiliation
MIT
Other Primary Investigator(s)
PI Affiliation
Harvard
Additional Trial Information
Status
On going
Start date
2008-03-10
End date
2018-03-10
Secondary IDs
Abstract
The Oregon Health Insurance Experiment is a randomized evaluation of the effect of expanding access to Medicaid. In 2008, the state of Oregon drew names by lottery for its Medicaid program for low-income, uninsured adults. This ongoing study represents a collaborative effort between researchers and the state of Oregon to use this opportunity to learn about the impact of Medicaid on a variety of outcomes including health care use, health outcomes, financial strain, and well-being of low income adults.
Registration Citation
Citation
Baicker, Kate and Amy Finkelstein. 2013. "The Oregon Health Insurance Experiment." AEA RCT Registry. August 07. https://doi.org/10.1257/rct.28-2.0.
Sponsors & Partners

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Experimental Details
Interventions
Intervention(s)
Treatment group: 29,834 people and 24,912 households selected in the lottery (the lottery winners)
Control group: 45,088 and 41,473 households not selected (the control group).

Adults randomly selected in the lottery were given the option to apply for Medicaid (specifically Oregon Health Plan Standard).Oregon Health Plan Standard provides comprehensive medical benefits, including prescription drugs, with no patient cost-sharing and low monthly premiums ($0 to $20, based on income), mostly through managed-care organizations.
Intervention Start Date
2008-03-10
Intervention End Date
2018-03-10
Primary Outcomes
Primary Outcomes (end points)
health care use, health, financial strain
Primary Outcomes (explanation)
Secondary Outcomes
Secondary Outcomes (end points)
Secondary Outcomes (explanation)
Experimental Design
Experimental Design
In early 2008, Oregon opened a waiting list for its Medicaid program for low-income adults that had previously been closed to new enrollment. Approximately 90,000 people signed up for the available 10,000 openings. The state drew names from this waiting list by lottery to fill the openings. Persons who were selected won the opportunity — for themselves and any household member — to apply for Oregon Health Plan Standard and were sent an application. Those who sent back their application and met eligibility requirements were enrolled in Oregon Health Plan Standard. This random selection allows researchers to gauge the causal effects of Medicaid. The study compiles rich data from many sources to examine a wide range of potential effects of insurance. Data include mail surveys, in-person interviews and health exams, and administrative data such as hospital records.
Experimental Design Details
Not available
Randomization Method
In 2008, the state of Oregon drew names by lottery. Randomization was done on state computer.
Randomization Unit
Household
Was the treatment clustered?
Yes
Experiment Characteristics
Sample size: planned number of clusters
66,385 households
Sample size: planned number of observations
74,922 people
Sample size (or number of clusters) by treatment arms
Treatment= 29,834 people and 24,912 households Control= 45,088 people and 41,473 households.
Minimum detectable effect size for main outcomes (accounting for sample design and clustering)
Supporting Documents and Materials

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IRB
INSTITUTIONAL REVIEW BOARDS (IRBs)
IRB Name
Massachusetts Institute of Technology
IRB Approval Date
2008-04-22
IRB Approval Number
0804002701
IRB Name
HSPH
IRB Approval Date
2008-10-05
IRB Approval Number
OHRA P17925
IRB Name
Providence: mail survey
IRB Approval Date
2008-04-22
IRB Approval Number
08-64A
IRB Name
Providence: admin and in-person
IRB Approval Date
2009-03-09
IRB Approval Number
09-26A
IRB Name
NBER
IRB Approval Date
2008-06-10
IRB Approval Number
FWA 3692
IRB Name
Portland State University
IRB Approval Date
2008-04-16
IRB Approval Number
HSRRC 08501
Analysis Plan
Analysis Plan Documents
Analysis_Plan_2010_12_01.pdf

MD5: 8d9b0fe0e83fef437f33e7bec4170e7d

SHA1: 960f8770229e0fa858bc8ac465e69eb837ffbf85

Uploaded At: August 07, 2013

Analysis_Plan_2012_04_16.pdf

MD5: 811f57175cd6243f7922d8d451dc6087

SHA1: b8998771bf861904b5eb7a97575e48956673654b

Uploaded At: August 07, 2013

Analysis_Plan_2013_03_06.pdf

MD5: a525344271955567c734e7ba72d198bb

SHA1: c3e56f6fbc13f441ea4d51d0276a2dc1aca4d75b

Uploaded At: August 07, 2013