instruments randomization and learning about development there is currently much debate about the effectiveness of foreign aid and about what kind of projects can engender economic development there is skepticism about the ability of econometric analysis to resolve these issues or of development agencies to learn from their own experience in response there is increasing use in development economics of randomized controlled trials rcts to accumulate credible knowledge of what works without overreliance on questionable theory or statistical methods when rcts are not possible the proponents of these methods advocate quasirandomization through instrumental variable iv techniques or natural experiments i argue that many of these applications are unlikely to recover quantities that are useful for policy or understanding two key issues are the misunderstanding of exogeneity and the handling of heterogeneity i illustrate from the literature on aid and growth actual randomization faces similar problems as does quasi randomization notwithstanding rhetoric to the contrary i argue that experiments have no special ability to produce more credible knowledge than other methods and that actual experiments are frequently subject to practical problems that undermine any claims to statistical or epistemic superiority i illustrate using prominent experiments in development and elsewhere as with iv methods rct based evaluation of projects without guidance from an understanding of underlying mechanisms is unlikely to lead to scientific progress in the understanding of economic development i welcome recent trends in development experimentation away from the evaluation of projects and toward the evaluation of theoretical mechanisms jel c21 f35 o19

a cautionary note on tests of overidentifying restrictions in this note we argue that tests of overidentifying restrictions give little information on the validity of the moment conditions implied by the underlying economic model and therefore are mute about the possibility of identifying the parameters of interest

censored quantile instrumental variable estimates of the price elasticity of expenditure on medical care efforts to control medical care costs depend critically on how individuals respond to prices i estimate the price elasticity of expenditure on medical care using a censored quantile instrumental variable cqiv estimator cqiv allows estimates to vary across the conditional expenditure distribution relaxes traditional censored model assumptions and addresses endogeneity with an instrumental variable my instrumental variable strategy uses a family member s injury to induce variation in an individual s own price across the conditional deciles of the expenditure distribution i find elasticities that vary from 0 76 to 1 49 which are an order of magnitude larger than previous estimates

moral hazard in health insurance do dynamic incentives matter using data from employer provided health insurance and medicare part d we investigate whether healthcare utilization responds to the dynamic incentives created by the nonlinear nature of health insurance contracts we exploit the fact that because annual coverage usually resets every january individuals who join a plan later in the year face the same initial spot price of healthcare but a higher expected end of year future price we find a statistically significant response of initial utilization to the future price rejecting the null that individuals respond only to the spot price we discuss implications for analysis of moral hazard in health insurance

can micro credit bring development abstract we examine the long run effects of micro credit on development in an occupational choice model similar to banerjee and newman jpe 1993 micro credit is modeled as a pure improvement in the credit market that opens up self employment options to some agents who otherwise could only work for wages or subsist micro credit can either raise or lower long run gdp since it can lower use of both subsistence and full scale industrial technologies it typically lowers long run inequality and poverty by making subsistence payoffs less widespread thus an equity efficiency tradeoff may be involved in the promotion of micro credit however in a worst case scenario micro credit has purely negative long run effects the key to micro credit s long run effects is found to be the graduation rate defined as the rate at which the self employed build up enough wealth to start full scale firms we distinguish between two avenues for graduation winner graduation of those who earn above average returns in self employment and saver graduation due to gradual accumulation of average returns in self employment long run development is not attainable via micro credit if winner graduation is the sole avenue for graduation in contrast if the saving rate and self employment returns of the average micro borrower are jointly high enough then micro credit can bring an economy from stagnation to full development through saver graduation thus the lasting effects of micro credit may partially depend on simultaneous facilitation of micro saving eventual graduation of the average borrower rather than indefinite retention should be the goal of micro banks if micro credit is to be a stepping stone to broad based development rather than at best an anti poverty tool

what does a deductible do the impact of cost sharing on health care prices quantities and spending dynamics measuring consumer responsiveness to medical care prices is a central issue in health economics and a key ingredient in the optimal design and regulation of health insurance markets we study consumer responsiveness to medical care prices leveraging a natural experiment that occurred at a large self insured firm which required all of its employees to switch from an insurance plan that provided free health care to a non linear high deductible plan the switch caused a spending reduction between 11 79 13 80 of total firm wide health spending we decompose this spending reduction into the components of i consumer price shopping ii quantity reductions and iii quantity substitutions finding that spending reductions are entirely due to outright reductions in quantity we find no evidence of consumers learning to price shop after two years in high deductible coverage consumers reduce quantities across the spectrum of health care services including potentially valuable care e g preventive services and potentially wasteful care e g imaging services we then leverage the unique data environment to study how consumers respond to the complex structure of the high deductible contract we find that consumers respond heavily to spot prices at the time of care and reduce their spending by 42 when under the deductible conditional on their true expected end of year shadow price and their prior year end of year marginal price in the first year post plan change 90 of all spending reductions occur in months that consumers began under the deductible with 49 of all reductions coming for the ex ante sickest half of consumers under the deductible despite the fact that these consumers have quite low shadow prices there is no evidence of learning to respond to the true shadow price in the second year post switch

demand elasticities and service selection incentives among competing private health plans we examine selection incentives by health plans while refining the selection index of mcguire et al 2014 to reflect not only service predictability and predictiveness but also variation in cost sharing risk adjusted profits profit margins and newly refined demand elasticities across 26 disaggregated types of service we contrast selection incentives measured by service selection elasticities across six plan types using privately insured claims data from 73 large employers from 2008 to 2014 compared to flat capitation concurrent risk adjustment reduces the elasticity by 47 prospective risk adjustment by 43 simple reinsurance system by 32 and combined concurrent risk adjustment with reinsurance by 60 reinsurance significantly reduces the variability of individual level profits but increases the correlation of expected spending with profits which strengthens selection incentives

the rand health insurance experiment three decades later we re present and re examine the analysis from the famous rand health insurance experiment from the 1970s on the impact of consumer cost sharing in health insurance on medical spending we begin by summarizing the experiment and its core findings in a manner that would be standard in the current age we then examine potential threats to the validity of a causal interpretation of the experimental treatment effects stemming from different study participation and differential reporting of outcomes across treatment arms finally we re consider the famous rand estimate that the elasticity of medical spending with respect to its out of pocket price is 0 2 emphasizing the challenges associated with summarizing the experimental treatment effects from non linear health insurance contracts using a single price elasticity

health insurance and the demand for medical care evidence from a randomized experiment we estimate how cost sharing the portion of the bill the patient pays affects the demand for medical services the data come from a randomized experiment a catastrophic insurance plan reduces expenditures 31 percent relative to zero out of pocket price the price elasticity is approximately 0 2 we reject the hypothesis that less favorable coverage of outpatient services increases total expenditure for example by deterring preventive care or inducing hospitalization

the response of drug expenditure to nonlinear contract design evidence from medicare part d we study the demand response to non linear price schedules using data on insurance contracts and prescription drug purchases in medicare part d we exploit the kink in individuals budget set created by the famous donut hole where insurance becomes discontinuously much less generous on the margin to provide descriptive evidence of the drug purchase response to a price increase we then specify and estimate a simple dynamic model of drug use that allows us to quantify the spending response along the entire non linear budget set we use the model for counterfactual analysis of the increase in spending from filling the donut hole as will be required by 2020 under the affordable care act in our baseline model which considers spending decisions within a single year we estimate that filling the donut hole will increase annual drug spending by about 150 or about 8 percent about one quarter of this spending increase reflects anticipatory behavior coming from beneficiaries whose spending prior to the policy change would leave them short of reaching the donut hole we also present descriptive evidence of cross year substitution of spending by individuals who reach the kink which motivates a simple extension to our baseline model that allows in a highly stylized way for individuals to engage in such cross year substitution our estimates from this extension suggest that a large share of the 150 drug spending increase could be attributed to cross year substitution and the net increase could be as little as 45 per year

deterrence by market sharing a strategic incentive for licensing the potential of an incumbent firm to retain its dominant position in a market is a focal point of the modem theory of industrial organization a recent literature examines this issue for markets in which challengers threaten an incumbent s position by engaging in research for a new technology richard gilbert and david newbery 1982 show that an incumbent firm with a firstmover advantage will preempt potential entrants by inventing a new technology slightly earlier than would its rivals in a stochastic r d therefore its introduction does not alter the decision to research when the pre innovation market is characterized by an incumbent and potential entrants stephen salant 1984 shows that licensing ex post to innovation can alter the research decision as anticipation of the returns from future licensing encourages research by the entrant as a counterpoint to the salant result i find that licensing ex ante to research may discourage further research by the entrant indeed this strategic incentive for licensing may be so strong as to persuade the incumbent as well as the entrant to terminate research activity to isolate this incentive for licensing from the one discussed by salant a simple model is constructed in which licensing of future technologies is not desirable anecdotal evidence suggests that the strategic incentive does lead innovators in some markets to license their technologies examples of this information sharing are prevalent in markets where technological change is rapid in the 1940 s standard oil of new jersey discovered a process for synthetic rubber it traded patent rights on this process for a synthetic oil production process discovered by farben a german rubber company in both the synthetic oil and synthetic rubber markets rival companies were department of economics scarsborough college university of toronto toronto ontario canada m5s lal i thank jon cohen and ron saunders for discussions that inspired this paper i am also grateful to yehuda kotowitz andy mclennan jennifer reinganum ralph winter myma wooders two anonymous referees and seminar participants at the university of toronto for helpful comments on earlier drafts

tiered co payments pricing and demand in reference price markets for pharmaceuticals health insurance companies curb price insensitive behavior and the moral hazard of insureds by means of cost sharing such as tiered co payments or reference pricing in drug markets this paper evaluates the effect of price limits below which drugs are exempt from co payments on prices and on demand first using a difference in differences estimation strategy we find that the new policy decreases prices by 5 percent for generics and increases prices by 4 percent for brand name drugs in the german reference price market second estimating a nested logit demand model we show that consumers appreciate co payment exempt drugs and calculate lower price elasticities for brand name drugs than for generics this explains the different price responses of brand name and generic drugs and shows that price related co payment tiers are an effective tool to steer demand to low priced drugs

strategic entry deterrence in analyzing deterrence of large scale entry two classes of entry barriers may be distinguished an innocent entry barrier is unintentionally erected as a side effect of innocent profit maximization in contrast a strategic entry barrier is purposely erected to reduce the possibility of entry two types of innocent barriers may also be distinguished a postentry absolute advantage has the property that if entry did occur the established firm would be at a profit advantage over the entrant examples are superior technology or product design patents and lower input prices a preentry asymmetry advantage arises from the fundamental preentry asymmetry between established firm and potential entrant before the entrant makes his entry decision the established firm has already committed resources this prior existence gives first move advantages the preentry asymmetry is independent of symmetry or asymmetry in the rules the equilibrium concept of the postentry game that might ensue even if the postentry game will be played according to nash cournot or entrant as leader rules the preentry leadership

price elasticity of expenditure across health care services policymakers in countries around the world are faced with rising health care costs and are debating ways to reform health care to reduce expenditures estimates of price elasticity of expenditure are a key component for predicting expenditures under alternative policies using unique individual level data compiled from administrative records from the chilean private health insurance market i estimate the price elasticity of expenditures across a variety of health care services i find elasticities that range between zero for the most acute service appendectomy and 2 08 for the most elective psychologist visit moreover the results show that at least one third of the elasticity is explained by the number of visits the rest is explained by the intensity of each visit finally i find that high income individuals are five times more price sensitive than low income individuals and that older individuals are less price sensitive than young individuals

the demand for episodes of treatment in the health insurance experiment abstract this paper analyzes claims data from the rand health insurance experiment which were grouped into episodes of treatment the insurance plans in the experiment have coinsurance and a cap on out of pocket spending using new statistical techniques to adjust for the increased sickliness of those who exceed the cap the effects of coinsurance on cost per episode and number of episodes are estimated cost sharing reduced the number of episodes but had little effect on cost per episode people in the experiment responded myopically as their current insurance status changed through the year the price elasticity of spending was about 0 2 throughout the range of coinsurance studied when data permit it the study of episodes complements analyses of annual medical spending by revealing more about how decisions to spend are made within the year

selection on moral hazard in health insurance economic analysis of market failure in insurance markets tends to analyze selection and moral hazard as distinct phenomena in this paper we explore the potential for selection on moral hazard in insurance markets by this we mean the possibility that moral hazard effects are heterogenous across individuals and that individuals selection of insurance coverage is affected by their anticipated behavioral response to coverage we examine these issues empirically in the context of employer provided health insurance in the united states specifically we break down the general

health care demand elasticities by type of service we estimate within year price elasticities of demand for detailed health care services using an instrumental variable strategy in which individual monthly cost shares are instrumented by employer year plan month average cost shares a specification using backward myopic prices gives more plausible and stable results than using forward myopic prices using 171 million person months spanning 73 employers from 2008 to 2014 we estimate that the overall demand elasticity by backward myopic consumers is 0 44 with higher elasticities of demand for pharmaceuticals 0 44 specialists visits 0 32 mris 0 29 and mental health substance abuse 0 26 and lower elasticities for prevention visits 0 02 and emergency rooms 0 04 demand response is lower for children in larger firms among hourly waged employees and for sicker people overall the method appears promising for estimating elasticities for highly disaggregated services although the approach does not work well on services that are very expensive or persistent

rational behavior in the presence of coverage ceilings and deductibles consumers of health care services with insurance plan features such as deductibles copayments and coverage ceilings in which the price of health care depends upon expenditures accumulated during a single year should rationally anticipate the impact of current consumption decisions on the price of health care later in the year we show that in the absence of wealth effects and risk aversion a utility maximizing consumer should base current consumption decisions on the expected end of year price of health care in a specific model with risk aversion and lumpy consumption decisions we show that the expected end of year price remains close to the true shadow price of health carefor plausible insurance plan and demand parameters we use this result in an econometric model of the demand for ambulatory mental health services

preemptive patenting and the persistence of monopoly this article takes a different tack and inquires whether institutions such as the patent system create opportunities for firms with monopoly power to maintain their monopoly power the results apply to other situations such as brand identification spatial location and capacity expansion which share the characteristic that early or preemptive actions may lower the returns to potential competitors

cost sharing and patterns of mental health care utilization deductibles and coverage ceilings are common features of health insurance this paper proposes and tests a new method for estimating the impact of these health coverage features on demand when total demand during a particular period is not known with certainty at the beginning of the period we use expected end of year price as a proxy for the notion of effective price first suggested by keeler et al 1982 in a two stage estimation procedure applying the method to the demand for ambulatory mental health care in the presence of a 500 coverage ceiling yields estimated demand responses similar to those obtained by other researchers

optimal patents with compulsory licensing this paper examines the use of compulsory lincensing as a policy to combat the monopoly problem associated with the patent system it introduces the notion of an optimal patent one where the patent life and the licensing royalty rate are both determined optimally under certain simplifying assumptions it is shown that the optimal patent will have an indefinite life for both process and product innovations some preliminary calculations suggest that the use of compulsory licensing may lead to substantial welfare improvements even if the patent life is left unchanged at 17 years