Volume 53 | Number 6 | December 2018

Abstract List

Momotazur Rahman Ph.D., David J. Meyers M.P.H., Vincent Mor Ph.D.


The Medicare Modernization Act of 2004 allowed Medicare Advantage () contracts to form provider networks in order to concentrate their patients among preferred providers. We focus on the skilled nursing facility () industry to assess patients’ health when treating s concentrate more patients from the same contract.

Data Sources/Study Setting

We use Medicare Beneficiary Summary File and Health, , and the Minimum Data Set for patient attributes and ,focus.org, and Nursing Home Compare for attributes. We include 1,069,436 enrollees newly admitted to between 2012 and 2014.

Study Design

Using a contract fixed‐effect model, we examine the effect of prevalence of a patient's contract in the treating on patient's health outcomes including 180‐day survival, 30‐day hospital readmission, 30‐day home discharge, and nursing home length of stay. We use an Instrumental Variable (), the expected share of admissions in a from patient's contract calculated using a McFadden choice model.

Principal Findings

We find no relationship between contract concentration and patients’ outcomes after applying the .


While plans appear to steer patients to specific s, we do not observe significant returns to patient outcomes related to concentration.