Tobias Müller, Mujaheed Shaikh & Lukas Kauer (2025), Retirement and Health Plan Choice, Social Science & Medicine, Vol.370, 117844.
Abstract: Many consumers exhibit choice persistence, often sticking with suboptimal or dominated health plans. We analyze the effect of retirement on health plan choice using a fuzzy regression discontinuity design that exploits Switzerland’s old-age pension legislation. Drawing on insurance claims data from 84,731 individuals aged 61 to 68 over the years 2006-2014, we find that retirement significantly increases switching from the standard model to managed care plans, which offer lower premiums but restrict access to specialist care. However, deductible choices remain largely unaffected, as retirees are no more likely to select the cost-minimizing deductible than their non-retired counterparts. We conclude that while retirement may encourage plan switching, many consumers still choose dominated options, underscoring the need for a richer policy framework that provides consumer guidance incorporating measures such as personalized information interventions and simplified choice architectures to promote better health plan choices.
Jana Bilger, Mark Pletscher & Tobias Müller (2024), Separating the Wheat from the Chuff: How to Measure Hospital Quality in Routine Data?, Health Services Research, Vol. 59, Issue 2.
Media: SWICA News, BFH News, NZZ am Sonntag
Raf Van Gestel, Nils Broekman & Tobias Müller (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.
Abstract: We study the link between department-wide surgeon supply and quality of care for two major elective medical procedures. Several countries have adopted policies to concentrate medical procedures in high-volume hospitals. While higher patient volumes might translate to higher quality, we provide evidence for a positive relationship between surgeon supply and hospital revision rates for hip and knee replacement surgery. Hence, hospital performance decreases with higher surgeon supply, and this finding holds conditional on patient volumes.
Tobias Müller, Christian Schmid & Michael Gerfin (2023), Rents for Pills: Financial Incentives and Physician Behavior, Journal of Health Economics, Vol. 37: 102711.
Abstract: We study the impact of financial incentives on the prescription behavior of physicians based on a recent reform in two large Swiss cities. The reform opened up an additional income channel for physician by allowing them to earn a markup on drugs they prescribe to their patients. We find that the reform leads to an increase in drug costs by about 4%–5% per patient translating to significantly higher physician earnings. The revenue increase can be decomposed into a substitution and rent-seeking component. Our analysis indicates that physicians engage in rent-seeking by substituting larger with smaller packages and by cherry-picking more profitable brands. Although patient health is not sacrificed, the rent-seeking behavior results in unnecessary costs for society.
Tobias Müller & Stefan Boes (2020), Disability Insurance Benefits and Labor Supply Decisions: Evidence from a Discontinuity in Benefit Awards, Empirical Economics, Vol. 58: pp.2513-2544.
Abstract: The effect of disability insurance (DI) benefits on the labor supply of individuals is a disputed topic in both academia and policy. We identify the impact of DI benefits on working full-time, working part-time or being out of the labor force by exploiting a discontinuity in the DI benefit award rate in Switzerland above the age of 56. Using rich survey data and a discrete endogenous switching model, we find that DI benefit receipt increases the probability of working part-time by approximately 32% points, decreases the probability of working full-time by approximately 35% points and has little effect on the probability of being out of the labor force for the average beneficiary. Looking at the treatment effect distribution, we find that male, middle- to high-income and relatively healthy DI beneficiaries are more likely to adjust their labor supply from full-time to part-time, whereas women, low-income and ill beneficiaries tend to drop out of the labor market. Our results shed new light on the mechanisms explaining low DI outflow rates and may help better target interventions.
Tobias Müller & Mujaheed Shaikh (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.
Abstract: This paper presents evidence on intra-household retirement externalities by assessing the causal effect of spousal retirement on various health behaviors and health status across 19 European countries. We identify partner's and own retirement effects by applying a fuzzy regression discontinuity design using retirement eligibility as exogenous instruments for spousal and own retirement status. We find significant increases in the frequency and intensity of alcohol consumption combined with a significant decrease in moderate physicial activity as a response to partner's retirement. In line with the existing literature, we find that own retirement has significant positive effects on engaging in moderate and vigorous physicial activities but also leads to a significant increase in the frequency of alcohol intake. Overall, subjective health is negatively affected by spousal retirement and positively by own retirement.
Cornel Kaufmann, Tobias Müller, Andreas Hefti & Stefan Boes (2018), Does Personalized Information Improve Health Plan Choices When Individuals Are Distracted?, Journal of Economic Behavior & Organization, Vol. 149: pp.197-214.
Abstract: Choice-based health insurance systems allow individuals to select a health plan that fits their needs. However, bounded rationality and limited attention may lead to sub-optimal insurance coverage and higher-than-expected out-of-pocket payments. In this paper, we study the impact of providing personalized information on health plan choices in a laboratory experiment. We seek to more closely mimic real-life choices by randomly providing an incentivized distraction to some individuals. We find that providing personalized information significantly improves health plan choices. The positive effect is even larger and longer-lasting if individuals are distracted from their original task. In addition to providing decision support, receiving personalized information restores the awareness of the choice setting to a level comparable to the case without distraction thus reducing inertia. Our results indicate that increasing transparency of the health insurance system and providing tailored information can help individuals to make better choices and reduce their out-of-pocket expenditures.
Raf Van Gestel, Tobias Müller & Johann Bosmans (2018), Learning from Failure in Healthcare: Dynamic Panel Evidence of a Physician Shock Effect, Health Economics, Vol. 27(09): pp.1340-1353.
Media: Healthcare Economist
Abstract: Procedural failures of physicians or teams in interventional healthcare may positively or negatively predict subsequent patient outcomes. We identify this effect by applying (non)linear dynamic panel methods to data from the Belgian transcatheter aorta valve implantation registry containing information on the first 860 transcatheter aorta valve implantation procedures in Belgium. We find that a previous death of a patient positively and significantly predicts subsequent survival of the succeeding patient. We find that these learning from failure effects are not long-lived and that learning from failure is transmitted across adverse events.
Raf Van Gestel, Tobias Müller & Johann Bosmans (2017), Does My High Blood Pressure Improve Your Survival? Overall and Subgroup Learning Curves in Health, Health Economics, Vol. 26(09): pp.1094-1109.
Abstract: Learning curves in health are of interest for a wide range of medical disciplines, healthcare providers, and policy makers. In this paper, we distinguish between three types of learning when identifying overall learning curves: economies of scale, learning from cumulative experience, and human capital depreciation. In addition, we approach the question of how treating more patients with specific characteristics predicts provider performance. To soften collinearity problems, we explore the use of least absolute shrinkage and selection operator regression as a variable selection method and Theil–Goldberger mixed estimation to augment the available information. We use data from the Belgian Transcatheter Aorta Valve Implantation (TAVI) registry, containing information on the first 860 TAVI procedures in Belgium. We find that treating an additional TAVI patient is associated with an increase in the probability of 2-year survival by about 0.16%-points. For adverse events like renal failure and stroke, we find that an extra day between procedures is associated with an increase in the probability for these events by 0.12%-points and 0.07%-points, respectively. Furthermore, we find evidence for positive learning effects from physicians' experience with defibrillation, treating patients with hypertension, and the use of certain types of replacement valves during the TAVI procedures.
Provider Behavior
Tobias Müller, Raf Van Gestel & Michael Gerfin, Professional Norms and Peer Comparison Feedback to Reduce Low-Value Care
IMPORTANCE: OECD estimates suggest that 20% of health care spending is wasteful or even harmful. Previous interventions have had limited success in discouraging low-value care in medical practice.
OBJECTIVE: To test whether personalized information combining professional norms and peer feedback can reduce the provision of low-value services in primary care.
METHODS: We conducted a nationwide randomized controlled trial among primary care physicians (PCPs) in Switzerland between November 2020 and November 2021. Eligible PCPs in the intervention groups were sent a personalized information letter combining professional norms and peer comparison feedback about two “Top 5” Choosing Wisely low-value services in primary care: vitamin D testing or generic substitution. Primary endpoints were the number of vitamin D tests in 100 patients and the share of generics prescribed to patients. We estimate average treatment effects based on linear regression models and apply the causal forest to assess effect heterogeneity between physician subgroups.
RESULTS: n=618 PCPs were randomized to the vitamin D intervention, n=597 to the generic prescribing arm, and another n=601 to the control group. The intervention reduced average vitamin D testing by 18.2%, representing a mean reduction of 3.66 tests in 100 patients (95% CI: -5.42 to -1.89; P<0.001). PCPs with high pre-intervention testing levels and older patients show the largest reductions. Average generic prescribing was not increased through the intervention (mean difference: +0.57 percentage points; 95% CI: -0.68 to +1.81 pp; P=0.37). 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). We found no adverse effects as PCPs with high baseline performance did not increase the targeted low-value services.
CONCLUSIONS: Letters that combine peer comparison feedback with professional norms can significantly reduce the use of low-value services in primary care without compromising patient health. Targeting all providers, rather than only those with low baseline performance, can greatly enhance the effectiveness of information-based interventions.
Media coverage: BFH News + Storys , SonntagsZeitung, CSS im dialog
Tobias Müller, Daniel Avdic & Raf Van Gestel, Nudging and Spillovers in Healthcare: Evidence From a Randomized Controlled Trial
ABSTRACT: To improve medical practice and reduce waste, information interventions such as audit & feedback and peer comparison feedback have gained popularity in healthcare. Based on a randomized controlled trial, we investigate whether peer comparison feedback targeting low-value care leads to spillover effects in non-targeted medical services. Estimating distributional treatment effects, we find that physicians’ total medical spending significantly increases despite increased adherence to the guidelines targeted by the intervention. We show that physicians over-compensate for the revenue losses from providing less low-value care by expanding service provision of revenue relevant services, whereas non-revenue relevant services are unaffected.
Tobias Müller, Manuel Langhart, Andreas Kohler & Raf Van Gestel, Tailoring the Nudge: Evidence from Two Randomized Trials on Peer Feedback, Physician Behavior and Health Spending
ABSTRACT: We conducted two large-scale randomized controlled trials to evaluate the effects of peer comparison feedback on physician behavior and medical spending in Switzerland. In both experiments, primary care physicians received personalized cost reports benchmarking their per-patient spending against that of their peers. In Experiment A, which targeted average cost providers, we find that while providers did not alter care related to their own revenue stream, they significantly increased non-revenue relevant services including pharmacy-dispensed medications and physiotherapy. The effects were largest among physicians with below-average baseline spending levels and a high-risk patient pool. In contrast, Experiment B focused on high-cost providers which were part of the official cost audit. Here, peer comparison feedback led to a substantial reduction in per-patient spending, primarily through lower consultation and physiotherapy spending. Our findings underscore the importance of tailoring nudges to the characteristics of targeted populations, as one-size-fits-all approaches can produce unintended consequences and may ultimately undermine policy goals.
Daniel Ammann, Lukas Kauer, Aurélien Sallin, & Tobias Müller, Manage Care Mechanisms, Patient Selection and Provider Behavior: How Do Provider Networks Reduce Medical Spending?
ABSTRACT: We examine the effects of managed care within a narrow provider network on health care spending, utilization, and quality in Switzerland. We find that network enrollment significantly reduces total annual spending by roughly $800 per patient, equivalent to 15% of pre-treatment costs. The cost savings primarily reflect a volume response, as network providers significantly reduce treatment intensity in outpatient services and medication costs. However, we find no evidence of the classic cost-quality trade-off: the average consultation time, visit frequency, and the provision of high-value care services remain unchanged. We further show that network enrollment systematically affects patient composition. Provider networks attract younger and healthier patients, indicating that observed spending reductions reflect both managed care effects and advantageous patient selection.
Policy Evaluation
Aurélien Sallin, Daniel Ammann, Caroline Bähler, Tobias Müller, Stefan Neuner-Jehle, Oliver Senn & Eva Blozik, The Impact of Choosing Wisely Recommendations and Coverage Restrictions on the Provision of Low-Value Care: An Interrupted Time-Series Analysis of Vitamin D Tests
Background: Interventions to reduce low-value care vary considerably in effectiveness. International consensus considers vitamin D blood testing in the general population as low-value care, which led to its inclusion in the Swiss Choosing Wisely™ recommendation in April 2021. In mid-2022, the Federal Office of Public Health further restricted basic health insurance coverage for the test.
Methods: We conducted a retrospective analysis of health insurance claims data covering about 880’000 Swiss residents in the compulsory health insurance market. To assess the effects of a) the Choosing Wisely recommendation and b) the federal coverage restriction, we applied interrupted time series models at the physician level, controlling for seasonal effects, physician fixed effects, and patient characteristics.
Results: The Choosing Wisely recommendation reduced the average monthly number of tests prescribed per physician per 100 consultations by approximately 5.98%. The federal coverage restriction led to a significant 57.82% drop in vitamin D testing per physician per 100 consultations in the 6 months following the intervention.
Conclusions: Medical recommendations marginally reduced low-value services, and their impact on clinical practice was limited. In contrast, federal coverage restrictions drastically reduced unnecessary testing. Multicomponent strategies combining evidence-based guidance for healthcare professionals, patient involvement, and national regulation related to reimbursement could be a best practice model for guiding public health stakeholders and politicians in order to reduce low-value care.
Dario Fauceglia, Tobias Müller, Thomas Leu & Regina Betz, How Do Firms Respond to a Rising Carbon Tax?
ABSTRACT: We analyze the effects of a uniform carbon tax, which increased five-fold between 2008 and 2014, on firms' carbon emissions in Switzerland. Based on a triple-difference design that uses firms’ initial carbon intensity as a measure of tax exposure and a within-firm counterfactual, we estimate an 8% reduction in emissions. This decarbonization was driven equally by reductions in energy consumption and shifts to a cleaner energy mix. Firms most exposed to the tax achieved the largest energy savings, while reductions in carbon intensity were partially attributable to pre-existing trends and varied across sectors. We estimate small but significant tax elasticities for heating and process fuel demand but find no significant net-of-tax price elasticities. Our findings suggest that the initial carbon tax of CHF 12 per ton of CO2 was insufficient to drive substantial emission reductions.
Lab Experiments
Andreas Hefti, Tobias Müller, Peiyao Shen & Ernst Fehr, Unleashing Cognitive Potential: The Role of External Attention Stimuli in Decision-Making
ABSTRACT: How do external stimuli influence decision-making and cognitive engagement? This study investigates the role of non-informative, salient changes in the decision environment in activating cognitive potential and enhancing decision quality. Using a novel dual-task experimental design, participants allocate attention between a contract-choice problem and a general-knowledge quiz. We find that sudden, non-informative external stimuli significantly improve decision-making performance, leading to higher rates of optimal contract choices and reduced excess costs. These findings challenge the assumption that individuals can fully self-regulate cognitive engagement and highlight the interplay between internal attention mechanisms and external triggers. Our results have implications for designing environments that harness cognitive activation to improve decision quality in real-world contexts such as financial planning, consumer behavior, and public policy.
Plan Choice
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.