Evidence map›Paper›PMID 35132619›Full record

ArticleHealth services research2022

Difference-in-differences for categorical outcomes.

John A Graves, Carrie Fry, J Michael McWilliams, Laura A Hatfield

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Article in Health services research, 2022. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 7 papers.

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0cells of the map it votes in
7citing papers in PubMed
–field-weighted citation impact
1 · What the graph read from it

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The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

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3 · Its place in the literature

Who cites it

7 citing papers in PubMed.

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4 · The record

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PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

5 · Who and what money

Authors and funding

4 authors.

John A GravesDepartment of Health Policy, Vanderbilt University School of Medicine, Nashville, Tennessee, USA.ORCID 0000-0002-8954-8202
Carrie FryDepartment of Health Policy, Vanderbilt University School of Medicine, Nashville, Tennessee, USA.ORCID 0000-0003-0661-847X
J Michael McWilliamsDepartment of Health Care Policy, Harvard Medical School, Boston, Massachusetts, USA.ORCID 0000-0002-4866-862X
Laura A HatfieldDepartment of Health Care Policy, Harvard Medical School, Boston, Massachusetts, USA.ORCID 0000-0003-0366-3929

Funding

Effects of Expanded Coverage on Access, Health Care and Health in the SouthR01CA189152 · NCI · VANDERBILT UNIVERSITY MEDICAL CENTER · PI GRAVES, JOHN A., MCWILLIAMS, JOHN MICHAEL · 2015 to 2019
$4.3M
NCI NIH HHS R01 CA189152
6 · The paper itself

Abstract

objectiveTo discuss and develop difference-in-difference estimators for categorical outcomes and apply them to estimate the effect of the Affordable Care Act's Medicaid expansion on insurance coverage. DATA SOURCES: Secondary analysis of Survey on Income and Program Participation (SIPP) data on health insurance coverage types before (January 2013) and after (December 2015) Medicaid expansion in 39 US states (19 expansion and 20 non-expansion). STUDY

designWe develop difference-in-difference methods for repeated measures (panel data) of categorical outcomes. We discuss scale-dependence of DID assumptions for marginal and transition effect estimates and specify a new target estimand: the difference between outcome category transitions under treatment versus no treatment. We establish causal assumptions about transitions that are sufficient to identify this and a marginal target estimand. We contrast the marginal estimands identified by the transition approach versus an additive assumption only about marginal evolution. We apply both the marginal and transition approaches to estimate the effects of Medicaid expansion on health insurance coverage types (employer-sponsored; other private, non-group; public; and uninsured). DATA EXTRACTION: We analyzed 16,027 individual survey responses from people aged 18-62 years in the 2014 SIPP panel. PRINCIPAL

findingsWe show that the two identifying assumptions are equivalent (on the scale of the marginals) if either the baseline marginal distributions are identical or the marginals are constant in both groups. Applying our transitions approach to the SIPP data, we estimate a differential increase in transitions from uninsured to public coverage and differential decreases in transitions from uninsured to private, non-group coverage and in remaining uninsured.

conclusionsBy comparing the assumption that marginals are evolving in parallel to an assumption about transitions across outcome values, we illustrate the scale-dependence of difference-in-differences. Our application shows that studying transitions can illuminate nuances obscured by changes in the marginals.

Indexed as

Insurance, HealthPatient Protection and Affordable Care ActHumansInsurance CoverageMedicaidMedically UninsuredUnited Statescontrol groupsdata scienceeconometrichealth care reformhealth policyinsurancemethodsmodelsregression analysisstatistical

Identifiers

PMID35132619
PMCPMC9108044

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Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.