Research

Peer-Reviewed Publications 

• Bilger, J., Pletscher, M. & Müller, T. (2024), Separating the Wheat from the Chuff: How to Measure Hospital Quality in Routine Data?, Health Services Research, Vol. 59, Issue 2.

  • Media coverage: SWICA News, BFH News

• Van Gestel, R., Broekman, N. & Müller, T. (2023), Surgeon Supply and Healthcare Quality: Are Revision Rates for Hip and Knee Replacements Lower in Hospitals That Employ More Surgeons?, Health Economics, Vol. 32(10): pp.2298-2321.

• Müller, T., Schmid, C., & Gerfin, M. (2023), Rents for Pills: Financial Incentives and Physician Behavior, Journal of Health Economics, Vol. 37: 102711.

  • Media coverage: Tages Anzeiger, Undark Magazine, Neue Zürcher Zeitung

• Müller, T. & Boes, S. (2020), Disability Insurance Benefits and Labor Supply Decisions: Evidence from a Discontinuity in Benefit Awards, Empirical Economics, Vol. 58: pp.2513-2544. 

• Müller, T. & Shaikh, M. (2018), Your Retirement and My Health Behavior: Evidence on Retirement Externalities from a Fuzzy Regression Discontinuity Design,  Journal of Health Economics, Vol. 57: pp.45-59.  

  • • This paper won the iHEA Student Best Paper Prize 2018

    • Media coverage: New York Times

• Kaufmann, C., Müller, T., Hefti, A. & Boes, S. (2018), Does Personalized Information Improve Health Plan Choices When Individuals Are Distracted?, Journal of Economic Behavior & Organization, Vol. 149: pp.197-214.

• Van Gestel, R., Müller, T. & Bosmans, J. (2018), Learning from Failure in Healthcare: Dynamic Panel Evidence of a Physician Shock Effect, Health Economics, Vol. 27(09): pp.1340-1353.

  • Media coverage: Healthcare Economist

• Van Gestel, R., Müller, T. & Bosmans, J. (2017), Does My High Blood Pressure Improve Your Survival? Overall and Subgroup Learning Curves in Health, Health Economics, Vol. 26(09): pp.1094-1109.  

  • • This paper won the iHEA Student Best Paper Prize 2017

Work in progress

Provider Behavior

• Tobias Müller, Raf Van Gestel & Michael Gerfin, Pairing Professional Norms and Peer Comparison Feedback to Reduce Low-Value Services in Primary Care: A Randomized Controlled Trial

  • IMPORTANCE: OECD estimates suggest that 20% of health care spending is wasteful or even harmful. It remains unclear how to best encourage physicians to reduce low-value services. 

  • OBJECTIVE: To test whether personalized information combining professional norms and peer feedback can reduce the provision of low-value services in primary care.

  • DESIGN: Pragmatic parallel-group design randomized trial conducted between November 2020 and November 2021.

  • SETTING: Nationwide trial in the Swiss primary care sector among physicians in solo practices.

  • PARTICIPANTS: Participants were 1,816 primary care physicians (PCPs) with low and high baseline performance in low-value care provision. PCPs with fewer than 100 patients per year, group practices and high-cost outliers were excluded from the trial.

  • INTERVENTION: PCPs in the intervention groups were sent information letters containing peer comparison feedback and professional norms about vitamin D testing (n = 618) or generic prescribing (n = 597). Physicians in the control group (n = 601) did not receive personalized feedback.

  • MAIN OUTCOMES: Primary outcomes were the number of vitamin D tests in 100 patients and the share of generics prescribed to patients.

  • RESULTS: The intervention reduced average vitamin D testing by 18.2% (mean difference: -3.66 tests in 100 patients; 95% CI: -5.42 to -1.89). PCPs conducted between 1 to 7 tests less in 100 patients one year after the intervention. The lowest 90% of low-value care providers accounted for more than 80% of the overall reduction in vitamin D testing (mean difference among bottom 90%: -2.74 tests in 100 patients; 95% CI: -4.12 to -1.25). The intervention did not significantly increase generic prescribing on average (mean difference: +0.57 pp; 95% CI: -0.68 to +1.81 pp). However, more than 19% of PCPs in the intervention group increased generic prescribing by up to +0.91 percentage points (95% CI: +0.21 to +1.61 pp). PCPs with high baseline performance did not increase low-value services.

  • CONCLUSIONS: Information interventions have the potential to significantly reduce low-value services in primary care at low costs. To increase their effectiveness, health policymakers should target all providers rather than focusing on providers with low baseline performance only.

    • Media coverage: BFH News + Storys , SonntagsZeitung

• Daniel Ammann, Lukas Kauer, Helge Liebert & Tobias Müller, Manage Care Mechanisms, Patient Selection and Provider Behavior: How Do Provider Networks Reduce Medical Spending?

  • ABSTRACT: We investigate the impact of managed care within a narrow provider network on health care spending, utilization, and quality of care in Switzerland. Based on a quasi-experiment, we find that provider network enrollment leads to significant reductions in overall medical spending by 15% (equivalent to -$798), primarily driven by savings in outpatient (-$374) and medication spending (-$454). These cost savings can be attributed to a reduction in the “quantity” of care, including fewer doctor consultations and increased generic substitution, rather than changes in health care prices or quality of care provided to patients. Importantly, network providers do not seem to trade off quality for lower costs.

Plan & Provider Choice

• Tobias Müller, Mujaheed Shaikh & Lukas Kauer, Retirement and Health Plan Choice

  • ABSTRACT: We analyze the effect of retirement on health plan choice using a natural experiment stemming from Switzerland's old-age pension legislation. Despite the majority of elderly individuals being inert in their plan choice, our analysis shows that retirement reduces inertia. We find that retirement increases switching to cheaper and more restricted managed care plans, while deductible choice remains unaffected. However, switching is concentrated among low-risk individuals leading to adverse selection in non-managed care plans. Our investigation of underlying mechanisms highlights the role of the income channel when explaining the retirement induced switching in health plans.

• Tamara Bischof, Michael Gerfin & Tobias Müller, Health Plan Choice and (In-)Attention

  • ABSTRACT: We study the role of inattention as a key source of inertia in health plan choices. Our structural model shows that more than 90% of the elderly in Switzerland are inattentive and thus stick to their previous plan. We estimate sizeable switching costs ($1,200) even conditional on attention explaining part of the observed choice persistence. Our policy simulations show that inattention leads to overspending and generates considerable welfare losses for most consumers. We further find that eliminating financially dominated plans from the choice set yields welfare gains for two thirds of individuals.

Other Research

• Dario Fauceglia, Tobias Müller, Thomas Leu & Regina Betz, How Do Firms Respond to a Rising Carbon Tax? 

  • ABSTRACT: We assess how firms responded to the introduction of a uniform carbon tax in Switzerland that was increased five-fold between 2008 and 2014. We find that firms reduced their carbon emissions by around 8 percent relative to a within-firm counterfactual, which we validate with a triple-difference research design that uses firms’ initial carbon intensity as a measure of tax exposure. Reductions in energy consumption and a lower carbon intensity of the energy mix contributed equally to firms’ decarbonization. While more tax exposed firms were mainly responsible for energy savings, the observed decline in carbon intensity was also driven by pre-existing trends and achieved heterogeneously across sectors. We estimate small but significant tax elasticities of demand for heating and process fuels in contrast to insignificant net of tax price elasticities. Our results indicate that the initial tax level was insufficient to induce a substantial decline in emissions.