Balancing Covariates via Propensity Score Weighting

Li, Fan; Morgan, Kari Lock; Zaslavsky, Alan M.

doi:10.1080/01621459.2016.1260466

Cited by 678 publications

(825 citation statements)

References 49 publications

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“…Third, we used propensity-score methods to balance observed patient characteristics between the ACO group and the control group within each HRR and study year (see the Supplementary Appendix). 26 Fourth, we conducted falsification tests treating 2010 or 2011 as a post-contract year.…”

Section: Methodsmentioning

confidence: 99%

Early Performance of Accountable Care Organizations in Medicare

et al. 2016

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BACKGROUND In the Medicare Shared Savings Program (MSSP), accountable care organizations (ACOs) have financial incentives to lower spending and improve quality. We used quasi-experimental methods to assess the early performance of MSSP ACOs. METHODS Using Medicare claims from 2009 through 2013 and a difference-in-differences design, we compared changes in spending and in performance on quality measures from before the start of ACO contracts to after the start of the contracts between beneficiaries served by the 220 ACOs entering the MSSP in mid-2012 (2012 ACO cohort) or January 2013 (2013 ACO cohort) and those served by non-ACO providers (control group), with adjustment for geographic area and beneficiary characteristics. We analyzed the 2012 and 2013 ACO cohorts separately because entry time could reflect the capacity of an ACO to achieve savings. We compared ACO savings according to organizational structure, baseline spending, and concurrent ACO contracting with commercial insurers. RESULTS Adjusted Medicare spending and spending trends were similar in the ACO cohorts and the control group during the precontract period. In 2013, the differential change (i.e., the between-group difference in the change from the precontract period) in total adjusted annual spending was −$144 per beneficiary in the 2012 ACO cohort as compared with the control group (P = 0.02), consistent with a 1.4% savings, but only −$3 per beneficiary in the 2013 ACO cohort as compared with the control group (P = 0.96). Estimated savings were consistently greater in independent primary care groups than in hospital-integrated groups among 2012 and 2013 MSSP entrants (P = 0.005 for interaction). MSSP contracts were associated with improved performance on some quality measures and unchanged performance on others. CONCLUSIONS The first full year of MSSP contracts was associated with early reductions in Medicare spending among 2012 entrants but not among 2013 entrants. Savings were greater in independent primary care groups than in hospital-integrated groups.

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Section: Methodsmentioning

confidence: 99%

Early Performance of Accountable Care Organizations in Medicare

et al. 2016

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“…In other words, the covariates need to be balanced between the two groups. Balancing covariates through propensity scores has been studied by several authors, including Austin (2008Austin ( , 2009), Imai and Ratkovic (2014) and Li, Morgan and Zaslavsky (2015). Rosenbaum and Rubin (1984) proposed using subclassification based on propensity scores, and Zanutto, Lu and Hornik (2005) provided an application of the subclassification method.…”

Section: The Propensity Score Adjusted Two-sample Empirical Likelihoodmentioning

confidence: 99%

Empirical Likelihood Methods for Complex Surveys With Data Missing-by-Design

Chen¹,

Thompson²,

Wu³

2018

STAT SINICA

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We consider nonrandomized pretest-posttest designs with complex survey data for observational studies. We show that two-sample pseudo empirical likelihood methods provide efficient inferences on the treatment effect, with a missing-by-design feature used for forming the two samples and the baseline information incorporated through suitable constraints. The proposed maximum pseudo empirical likelihood estimators of the treatment effect are consistent and pseudo empirical likelihood ratio confidence intervals are constructed through bootstrap calibration methods. The proposed methods require estimation of propensity scores which depend on the underlying missing-by-design mechanism.A simulation study is conducted to examine finite sample performances of the proposed methods under different scenarios of nonignorable and ignorable missing patterns. An application to the International Tobacco Control Policy Evaluation Project Four Country Surveys is also presented to demonstrate the use of the proposed methods for examining the mode effect in survey data collection.

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“…To assess the impact of selected treatments (ie, beta blockers, calcium channel blockers, digoxin and oral anticoagulants) on outcomes among patients with COPD, we used Cox proportional hazards models in which the association of treatment at baseline with outcomes was adjusted with overlap weighting of the propensity to receive that treatment 14. Overlap weighting places the greatest weight on patients who are most comparable between the two treatment groups of interest (here beta blocker vs calcium channel blocker, beta blocker vs digoxin or oral anticoagulant vs no oral anticoagulant).…”

Section: Methodsmentioning

confidence: 99%