Reading list

A Structural Approach to Market Definition With an Application to the Hospital Industry, by Martin Gaynor, Samuel A. Kleiner, William B. Vogt

Market definition is essential to merger analysis. Because no standard approach to market definition exists, opposing parties in antitrust cases often disagree about the extent of the market. These differences have been particularly relevant in the hospital industry, where the courts have denied seven of eight merger challenges since 1994, due largely to disagreements over geographic market definition. We compare geographic markets produced using common ad hoc methodologies to a method that directly applies the “SSNIP test” to hospitals in California using a structural model. Our results suggest that previously employed methods overstate hospital demand elasticities by a factor of 2.4 to 3.4 and define larger markets than would be implied by the merger guidelines’s hypothetical monopolist test. The use of these methods in differentiated product industries may lead to mistaken geographic market delineation, and was likely a contributing factor to the permissive legal environment for hospital mergers.

Insurance Mandates and Mammography, by Marianne P. Bitler, Christopher S. Carpenter

Recently adopted federal health reform requires insurers to cover mammograms without cost-sharing. We examine similar state insurance mandates that vary substantially in the timing of adoption and in specifying the ages of women eligible for different mammography benefits. In triple differences models we find that mandates requiring coverage of annual mammograms significantly increased past year mammography screenings by about 8 percent, representing over 800,000 additional women screened from 1987-2000. Mandates that explicitly prohibit deductibles are especially effective at increasing screenings among high school dropouts, suggesting that federal health reform is likely to further increase use of screening mammography.

The Effect of the MassHealth Hospital Pay-for-Performance Program on Quality, by Andrew M. Ryan and Jan Blustein

Objective. To test the effect of Massachusetts Medicaid’s (MassHealth) hospital-based pay-for-performance (P4P) program, implemented in 2008, on quality of care for pneumonia and surgical infection prevention (SIP).

Data. Hospital Compare process of care quality data from 2004 to 2009 for acute care hospitals in Massachusetts (N=62) and other states (N=3,676) and American Hospital Association data on hospital characteristics from 2005.

Study Design. Panel data models with hospital fixed effects and hospital-specific trends are estimated to test the effect of P4P on composite quality for pneumonia and SIP. This base model is extended to control for the completeness of measure reporting. Further sensitivity checks include estimation with propensity-score matched control hospitals, excluding hospitals in other P4P programs, varying the time period during which the program was assumed to have an effect, and testing the program effect across hospital characteristics.

Principal Findings. Estimates from our preferred specification, including hospital fixed effects, trends, and the control for measure completeness, indicate small and nonsignificant program effects for pneumonia (−0.67 percentage points, p>.10) and SIP (−0.12 percentage points, p>.10). Sensitivity checks indicate a similar pattern of findings across specifications.

Conclusions. Despite offering substantial financial incentives, the MassHealth P4P program did not improve quality in the first years of implementation.

[I can’t get yet] Mental health parity legislation, cost-sharing and substance-abuse treatment admissions, by Dhaval Dave and Swati Mukerjee

Treatment is highly cost-effective in reducing an individual’s substance abuse (SA) and associated harms. However, data from Treatment Episodes (TEDS) indicate that per capita treatment admissions substantially lagged behind increases in heavy drug use from 1992 to 2007. Only 10% of individuals with clinical SA disorders receive treatment, and almost half who forgo treatment point to accessibility and cost constraints as barriers to care. This study investigates the impact of state mental health and SA parity legislation on treatment admission flows and cost-sharing. Fixed effects specifications indicate that mandating comprehensive parity for mental health and SA disorders raises the probability that a treatment admission is privately insured, lowering costs for the individual. Despite some crowd-out of charity care for private insurance, mandates reduce the uninsured probability by a net 2.4 percentage points. States mandating comprehensive parity also see an increase in treatment admissions. Thus, increasing cost-sharing and reducing financial barriers may aid the at-risk population in obtaining adequate SA treatment. Supply constraints mute effect sizes, suggesting that demand-focused interventions need to be complemented with policies supporting treatment providers. These results have implications for the effectiveness of the 2008 Federal Mental Health Parity and Addiction Equity Act in increasing SA treatment admissions and promoting cost-sharing.

That instrument is lousy! In search of agreement when using instrumental variables estimation in substance use research, by Michael T. French and Ioana Popovici

The primary statistical challenge that must be addressed when using cross-sectional data to estimate the consequences of consuming addictive substances is the likely endogeneity of substance use. While economists are in agreement on the need to consider potential endogeneity bias and the value of instrumental variables estimation, the selection of credible instruments is a topic of heated debate in the field. Rather than attempt to resolve this debate, our paper highlights the diversity of judgments about what constitutes appropriate instruments for substance use based on a comprehensive review of the economics literature since 1990. We then offer recommendations related to the selection of reliable instruments in future studies.

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