Impact of community masking on COVID-19: A cluster-randomized trial in Bangladesh.

We conducted a cluster-randomized trial to measure the effect of community-level mask distribution and promotion on symptomatic severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections in rural Bangladesh from November 2020 to April 2021 (N = 600 villages, N = 342,183 adults). We cross-randomized mask type (cloth versus surgical) and promotion strategies at the village and household level. Proper mask-wearing increased from 13.3% in the control group to 42.3% in the intervention arm (adjusted percentage point difference = 0.29; 95% confidence interval = [0.26, 0.31]). The intervention reduced symptomatic seroprevalence (adjusted prevalence ratio = 0.91 [0.82, 1.00]), especially among adults ≥60 years old in villages where surgical masks were distributed (adjusted prevalence ratio = 0.65 [0.45, 0.85]). Mask distribution with promotion was a scalable and effective method to reduce symptomatic SARS-CoV-2 infections.

Mortality Effects and Choice Across Private Health Insurance Plans.

Competition in health insurance markets may fail to improve health outcomes if consumers are not able to identify high quality plans. We develop and apply a novel instrumental variables framework to quantify the variation in causal mortality effects across plans and how much consumers attend to this variation. We first document large differences in the observed mortality rates of Medicare Advantage plans within local markets. We then show that when plans with high (low) mortality rates exit these markets, enrollees tend to switch to more typical plans and subsequently experience lower (higher) mortality. We derive and validate a novel "fallback condition" governing the subsequent choices of those affected by plan exits. When the fallback condition is satisfied, plan terminations can be used to estimate the relationship between observed plan mortality rates and causal mortality effects. Applying the framework, we find that mortality rates unbiasedly predict causal mortality effects. We then extend our framework to study other predictors of plan mortality effects and estimate consumer willingness to pay. Higher spending plans tend to reduce enrollee mortality, but existing quality ratings are uncorrelated with plan mortality effects. Consumers place little weight on mortality effects when choosing plans. Good insurance plans dramatically reduce mortality, and redirecting consumers to such plans could improve beneficiary health.

Prescription Drug Use under Medicare Part D: A Linear Model of Nonlinear Budget Sets.

Medicare Part D enrollees face a complicated decision: they dynamically choose prescription drug consumption in each period given difficult-to-find prices and a non-linear budget set. We use Part D claims data to estimate a flexible model of consumption that accounts for non-linear prices, dynamic responses, and salience. We use reduced form price responses from a linear regression of consumption on coverage range prices to compare performance under several models of behavior. We find small price elasticities, substantial myopia, and that salient characteristics impact consumption beyond their effect on prices. A hyperbolic discounting model with salience fits the data best.

Trends and Variation in the Utilization and Diagnostic Yield of Chest Imaging for Medicare Patients With Suspected Pulmonary Embolism in the Emergency Department.

OBJECTIVE: The purpose of this study is to assess trends and variation in chest CT utilization in the emergency department (ED) and its diagnostic yield for suspected pulmonary embolism (PE) among a national sample of Medicare beneficiaries. The relationship between hospital and provider characteristics is also discussed. MATERIALS AND METHODS: We conducted an observational analysis of Medicare beneficiaries evaluated in the ED for suspected PE from 2000 to 2009. Standard Medicare analytic files representing a 20% sample of fee-for-service beneficiaries were linked to the American Hospital Association Annual Survey of Hospitals, American Medical Association Physician Masterfile, Medicare Physician Identification and Eligibility Registry, and Dartmouth Atlas Project to calculate geographic- and physician-level chest CT utilization (i.e., the proportion of ED visits involving chest CT examination for suspected PE) and diagnostic yield (i.e., the proportion of chest CT examinations with a positive PE diagnosis). RESULTS: Of 2.5 million ED visits, 2.5% (n = 164,274) included chest CT for suspected PE; 6.2% visits (n = 10,121) resulted in positive findings for PE. Between 2000 and 2009, chest CT utilization increased fivefold. Geographic variation in CT utilization (median, 2.38%; interquartile range [IQR], 1.91-2.92%) and diagnostic yield (median, 6.31%; IQR, 5.11-7.66%) was observed between 306 hospital referral regions. Physician use of imaging was explained by greater experience (lower utilization and higher yield) and emergency medicine board certification (lower utilization and equivalent yield). CONCLUSION: CT utilization in the ED for suspected PE has steadily risen, whereas diagnostic yields have declined over time. Wide variation in practice is observed at the physician and geographic levels and is explained by several physician and hospital characteristics. Taken together, our findings suggest a substantial inefficiency of chest CT use and substantial opportunities for improvement.

Choice Inconsistencies among the Elderly: Evidence from Plan Choice in the Medicare Part D Program: Reply.

We explore the in- and out- of sample robustness of tests for choice inconsistencies based on parameter restrictions in parametric models, focusing on tests proposed by Ketcham, Kuminoff and Powers (KKP). We argue that their non-parametric alternatives are inherently conservative with respect to detecting mistakes. We then show that our parametric model is robust to KKP's suggested specification checks, and that comprehensive goodness of fit measures perform better with our model than the expected utility model. Finally, we explore the robustness of our 2011 results to alternative normative assumptions highlighting the role of brand fixed effects and unobservable characteristics.

The Determinants of Productivity in Medical Testing: Intensity and Allocation of Care.

A large body of research has investigated whether physicians overuse care. There is less evidence on whether, for a fixed level of spending, doctors allocate resources to patients with the highest expected returns. We assess both sources of inefficiency exploiting variation in rates of negative imaging tests for pulmonary embolism. We document enormous across-doctor heterogeneity in testing conditional on patient population, which explains the negative relationship between physicians' testing rates and test yields. Furthermore, doctors do not target testing to the highest risk patients, reducing test yields by one third. Our calibration suggests misallocation is more costly than overuse.

Evolving Choice Inconsistencies in Choice of Prescription Drug Insurance.

We study choice over prescription insurance plans by the elderly using government administrative data to evaluate how these choices evolve over time. We find large "foregone savings" from not choosing the lowest cost plan that has grown over time. We develop a structural framework to decompose the changes in "foregone welfare" from inconsistent choices into choice set changes and choice function changes from a fixed choice set. We find that foregone welfare increases over time due primarily to changes in plan characteristics such as premiums and out-of-pocket costs; we estimate little learning at either the individual or cohort level.

Choice Inconsistencies among the Elderly: Evidence from Plan Choice in the Medicare Part D Program: Reply.

We explore the in- and out-of-sample robustness of tests for choice inconsistencies based on parameter restrictions in parametric models, focusing on tests proposed by Ketcham, Kuminoff, and Powers (2016). We argue that their nonparametric alternatives are inherently conservative with respect to detecting mistakes. We then show that our parametric model is robust to KKP's suggested specification checks, and that comprehensive goodness of fit measures perform better with our model than the expected utility model.Finally, we explore the robustness of our 2011 results to alternative normative assumptions highlighting the role of brand fixed effects and unobservable characteristics.

The Determinants of Productivity in Medical Testing: Intensity and Allocation of Care.

A large body of research has investigated whether physicians overuse care. There is less evidence on whether, for a fixed level of spending, doctors allocate resources to patients with the highest expected returns. We assess both sources of inefficiency, exploiting variation in rates of negative imaging tests for pulmonary embolism. We document enormous across-doctor heterogeneity in testing conditional on patient population, which explains the negative relationship between physicians' testing rates and test yields. Furthermore, doctors do not target testing to the highest risk patients, reducing test yields by one-third. Our calibration suggests misallocation is more costly than overuse.

Choice Inconsistencies Among the Elderly: Evidence from Plan Choice in the Medicare Part D Program.

We evaluate the choices of elders across their insurance options under the Medicare Part D Prescription Drug plan, using a unique data set of prescription drug claims matched to information on the characteristics of choice sets. We document that elders place much more weight on plan premiums than on expected out of pocket costs; value plan financial characteristics beyond any impacts on their own financial expenses or risk; and place almost no value on variance reducing aspects of plans. Partial equilibrium welfare analysis implies that welfare would have been 27% higher if patients had all chosen rationally.

Heterogeneity in Choice Inconsistencies Among the Elderly: Evidence from Prescription Drug Plan Choice.

This paper investigates the degree to which choice inconsistencies documented in the context of Medicare Part D plan choice vary across consumers and geographic regions. Our main finding is that there is surprisingly little variation: regardless of age, gender, predicted drug expenditures or the predictability of drug demand consumers underweight out of pocket costs relative to premiums and fail to consider the individualized consequences of plan characteristics; as a result, they frequently choose plans which are dominated in the sense that an alternative plan provides better risk protection at a lower cost. We find limited evidence that the sickest individuals had more difficulty with plan choice, and we document that much of the variation in potential cost savings across states comes from variation in choice sets, not variation in consumers' ability to choose.