Research

Working Papers

“How Do Primary Care Physicians Influence Healthcare? Evidence on Practice Styles and Switching Costs from Medicare”

Primary care physicians have a central role in medicine, yet little is known about their influence on healthcare utilization. Using a model that includes both patient fixed effects and physician fixed effects, I find that differences in primary care physician practice styles explain 1.5% of the variation in utilization within healthcare markets as measured by spending, and patients who involuntarily switch physicians incur $390-$610 in additional spending around these switches. With these results, I construct counterfactuals and find that policies that reallocate patients across primary care physicians may be counterproductive due to modest long-run savings and substantial short-run switching costs.

Works in Progress

“Influence of Provider Continuity on Patient Health-Related Behavior and Outcomes”

Provider discontinuities, which I define as breaks in provider continuity, can affect healthcare through multiple channels. Patients face search and transaction costs in obtaining new providers and may delay care. Patients may temporarily use more care when visiting new providers (e.g., due to information acquisition). I investigate the effects of primary care physician (PCP) discontinuities on patient health-related outcomes and the heterogeneity of these effects across patients. I use two empirical strategies. First, I estimate the effects of discontinuities using an event study research design with discontinuity events that are exogenous to patients, including PCP retirements and relocations. Second, among patients whose PCPs relocate within their original healthcare markets, I compare the effects of discontinuities with individual PCPs and the effects of discontinuities with physician group practices using an instrumental variables approach. Since patients make endogenous decisions on whether to retain these PCPs, I construct an instrument for discontinuity that is a function of a patient’s distance to the PCP’s new location, which is plausibly exogenous to the patient. My analysis uses Original Medicare claims data from 1999 to 2012. Preliminary results show that a PCP discontinuity causes an immediate decline in primary care visits, which comes from a decline in established patient office visits and is partially offset by an increase in new patient office visits. This result suggests that patients experience delays in care and switch provider practice groups in response to discontinuities. Patients increase their use of urgent care clinics and emergency room visits, potentially as a result of inaccessible, delayed, or inadequate primary care. Finally, patients experience short-term increases in certain types of medical care, including imaging and tests as well as low-value care.

“Physician Supply, Insurance, and Patient Healthcare Access: Evidence from Massachusetts Psychiatrists”

Patients may not have timely access to healthcare within their health insurance plan networks and may choose to seek out-of-network care. I investigate the effects of local physician supply and insurance plan networks on patients’ choices of healthcare providers and the timeliness of their visits. The context of my study is psychiatry, a specialty with among the greatest national physician shortages and the lowest rates of insurance acceptance. My empirical strategy uses (a) panel variation in health insurance plan networks and physician payment rates and (b) two policy changes during my sample period: (i) the phase-out of outpatient mental health services limitation in Medicare from 2010 to 2014, which could impact patient demand and physician payment rates set by health insurance plans for psychiatric services, and (ii) a coding change between 2012 and 2013 for psychiatric services, which could have different revenue impacts across psychiatrists. My analysis uses the Massachusetts All Payer Claims Database from 2010 to 2014. I construct and estimate a discrete choice model of patient demand for timely services – in which patients choose between in-network and out-of-network care – and a model of physician supply with capacity constraints. My descriptive analysis thus far shows that wait times, as proxied by several observable measures, are shorter for out-of-network visits than for in-network visits. Patients pay more and insurance companies pay less for out-of-network visits than for in-network visits. These findings suggest that patients likely face a tradeoff between lower prices in-network and shorter wait times out-of-network.

“How Much Do Patients Value Their Physicians?”