Academic Work

Working Paper
Yeomans, Mike, Anuj K. Shah, Sendhil Mullainathan, and Jon Kleinberg. Working Paper. “Making Sense of Recommendations”. recommenders55.pdf
Mullainathan, Sendhil, and Eldar Shafir. 2014. “Freeing Up Intelligence.” Scientific American.Abstract

Imagine sitting in an office located near the railroad tracks. Trains rattle by several times an hour. As you try to concentrate, the rumble of every train pulls you away from what you are doing. You need time to refocus, to collect your thoughts. Worse, just when you have settled back in, another train hurtles by. This description mirrors the conditions of a school in New Haven located next to a noisy railroad line. In the early 1970s two researchers decided to measure the impact of this noise on students. They noted that only one side of the school faced the tracks, so the students in classrooms on that side were particularly exposed to the noise but were otherwise similar to their fellow students.

Niehaus, Paul, Antonia Attanassova, Marianne Bertrand, and Sendhil Mullainathan. 2013. “Targeting with Agents.” American Economic Journal: Economic Policy 5 (1): 206-38.Abstract
Targeting assistance to the poor is a central problem in development. We study the problem of designing a proxy means test when the implementing agent is corruptible. Conditioning on more poverty indicators may worsen targeting in this environment because of a novel tradeo between statistical accuracy and enforceability. We then test necessary conditions for this tradeo using data on Below Poverty Line card allocation in India. Less eligible households pay larger bribes and are less likely to obtain cards, but widespread rule violations yield a de facto allocation much less progressive than the de jure one. Enforceability appears to matter
Brown, Jeffrey R, Jeffrey R Kling, Sendhil Mullainathan, and Marian V Wrobel. 2013. Framing Lifetime Income. National Bureau of Economic Research.Abstract
We provide evidence that individuals optimize imperfectly when making annuity decisions, and this result is not driven by loss aversion. Life annuities are more attractive when presented in a consumption frame than in an investment frame. Highlighting the purchase price in the consumption frame does not alter this result. The level of habitual spending has little interaction with preferences for annuities in the consumption frame. In an investment frame, consumers prefer annuities with principal guarantees; this result is similar for guarantee amounts below, at, and above the purchase price. We discuss implications for the retirement services industry and its regulators.
Mani, Anandi, Sendhil Mullainathan, Eldar Shafir, and Jiaying Zhao. 2013. “Poverty Impedes Cognitive Function.” science 341 (6149): 976-980.Abstract
The poor often behave in less capable ways, which can further perpetuate poverty. We hypothesize that poverty directly impedes cognitive function and present two studies that test this hypothesis. First, we experimentally induced thoughts about finances and found that this reduces cognitive performance among poor but not in well-off participants. Second, we examined the cognitive function of farmers over the planting cycle. We found that the same farmer shows diminished cognitive performance before harvest, when poor, as compared with after harvest, when rich. This cannot be explained by differences in time available, nutrition, or work effort. Nor can it be explained with stress: Although farmers do show more stress before harvest, that does not account for diminished cognitive performance. Instead, it appears that poverty itself reduces cognitive capacity. We suggest that this is because poverty-related concerns consume mental resources, leaving less for other tasks. These data provide a previously unexamined perspective and help explain a spectrum of behaviors among the poor. We discuss some implications for poverty policy.
and Sendhil Mullainathan, Joshua Schwartzstein, William Congdon J. 2012. “A Reduced-Form Approach to Behavioral Public Finance.” Annual Review of Economics 4: 511-540.Abstract
Research in behavioral public finance has blossomed in recent years, producing diverse empirical and theoretical insights. This article develops a single framework with which to understand these advances. Rather than drawing out the consequences of specific psychological assumptions, the ramework takes a reducedform approach to behavioral modeling. It emphasizes the difference between decision and experienced utility that underlies most behavioral models. We use this framework to examine the behavioral implications for canonical public finance problems involving the provision of social insurance, commodity taxation, and correcting externalities. We show how deeper principles undergird much work in this area and that many insights are not specific to a single psychological assumption.
Redelmeier, Donald A, William K Chan, Sendhil Mullainathan, and Eldar Shafir. 2012. “Social benefit payments and acute injury among low-income mothers.” Open medicine 6 (3): e101-e108.Abstract
Mullainathan, Sendhil, Jeffrey R Kling, Eldar Shafir, Lee Vermeulen, and Marian V Wrobel. 2012. “Comparison Friction: Experimental Evidence from Medicare Drug Plans.” Quarterly Journal of Economics 127 (1): 199-235.Abstract
Consumers need information to compare alternatives for markets to function efficiently. Recognizingthis, publicpolicies oftenpaircompetitionwitheasyaccess tocomparative information. The implicit assumption is that comparison friction—thewedgebetweentheavailability of omparativeinformationandconsumers’ use of it—is inconsequential becausewheninformationis readilyavailable, consumers will access this information and make effective choices. We examine the extent of comparison friction in the market for Medicare Part D prescription drug plans in the United States. In a randomized field experiment, an intervention group received a letter with personalized cost information. That information was readily available for free and widely advertised. However, this additional step—providing the information rather than having consumers actively access it—had an impact. Plan switching was 28% in the intervention group, versus 17% in the comparison group, and the intervention caused an average decline in predicted consumer cost of about $100 a year among letter recipients—roughly 5% of the cost in the comparison group. Our results suggest that comparison friction can be large even when the cost of acquiring information is small and may be relevant for a wide range of public policies that incorporate consumer choice
Mullainathan, Sendhil, Lawrence F Katz, William J Congdon, and Linda Babcock. 2012. “Notes on Behavioral Economics and Labor Market Policy.” IZA Journal of Labor Policy 1 (2).Abstract
Labor market policies succeed or fail at least in part depending on how well they reflect or account for behavioral responses. Insights from behavioral economics, which allow for realistic deviations from standard economic assumptions about behavior, have consequences for the design and functioning of labor market policies. We review key implications of behavioral economics related to procrastination, difficulties in dealing with complexity, and potentially biased labor market expectations for the design of selected labor market policies including unemployment compensation, employment services and job search assistance, and job training.
Banerjee, Abhijit V, Rema Hanna, and Sendhil Mullainathan. 2012. “Corruption.” Handbook of Organizational Economics.Abstract
In this paper, we provide a new framework for analyzing corruption in public bureaucracies. The standard way to model corruption is as an example of moral hazard, which then leads to a focus on better monitoring and stricter penalties with the eradication of corruption as the final goal. We propose an alternative approach which emphasizes why corruption arises in the first place. Corruption is modeled as a consequence of the interaction between the underlying task being performed by bureaucrat, the bureaucrat's private incentives and what the principal can observe and control. This allows us to study not just corruption but also other distortions that arise simultaneously with corruption, such as red-tape and ultimately, the quality and efficiency of the public services provided, and how these outcomes vary depending on the specific features of this task. We then review the growing empirical literature on corruption through this perspective and provide guidance for future empirical research.
Allcott, Hunt, Sendhil Mullainathan, and Dmitry Taubinsky. 2012. “Energy Policy with Externalities and Internalities”.Abstract
We analyze optimal policy when consumers of energy-using durables undervalue energy costs relative to their private optima. First, there is an Internality Dividend from Externality Taxes: aside from reducing externalities, they also offset distortions from underinvestment in energy efficiency. Discrete choice simulations of the auto market suggest that the Internality Dividend could more than double the social welfare gains from a carbon tax at marginal damages. Second, we develop the Internality Targeting Principle: the optimal combination of multiple instruments depends on the average internality of the consumers marginal to each instrument. Because consumers who undervalue energy costs are mechanically less responsive to energy taxes, the optimal policy will tend to involve an energy tax below marginal damages coupled with a large subsidy for energy efficient products. Third, although the exact optimal policy depends on joint distributions of unobservables which would be difficult to estimate, we develop formulas to closely approximate optimal policy and welfare effects based on reduced form “sufficient statistics” that can be estimated using variation in product prices and energy costs.
Baicker, Katherine, William J Congdon, and Sendhil Mullainathan. 2012. “Health Insurance Coverage and Take‐Up: Lessons from Behavioral Economics.” Milbank Quarterly 90 (1): 107-134.Abstract
Context: Millions of uninsured Americans ostensibly have insurance available to them—many at very low cost—but do not take it up. Traditional economic analysis is based on the premise that these are rational decisions, but it is hard to reconcile observed enrollment patterns with this view. The policy prescriptions that the traditional model generates may thus fail to achieve their goals. Behavioral economics, which integrates insights from psychology into economic analysis, identifies important deviations from the traditional assumptions of rationality and can thus improve our understanding of what drives health insurance take-up and improved policy design.
Shah, Anuj K, Sendhil Mullainathan, and Eldar Shafir. 2012. “Some Consequences of Having Too Little.” Science Magazine, 682-685.Abstract
Poor individuals often engage in behaviors, such as excessive borrowing, that reinforce the conditions of poverty. Some explanations for these behaviors focus on personality traits of the poor. Others emphasize environmental factors such as housing or financial access. We instead consider how certain behaviors stem simply from having less. We suggest that scarcity changes how people allocate attention: It leads them to engage more deeply in some problems while neglecting others. Across several experiments, we show that scarcity leads to attentional shifts that can help to explain behaviors such as overborrowing. We discuss how this mechanism might also explain other puzzles of poverty.
Mullainathan, Sendhil, Emir Kamenica, and Richard Thale. 2011. “Helping Consumers Know Themselves.” American Economic Review Papers and Proceedings 2011: 417-422.Abstract
Firms sometimes know more about a consumer's expected usage than the consumer herself. We explore the consequences of this reversal in the information asymmetry. We analyze the consequences of making consumers more informed about themselves. While making consumers more informed decreases their expenditure conditional on a given set of prices, equilibrium prices may increase, offsetting the direct benefit of information. We discuss theoretical and practical issues surrounding so-called RECAP regulation that would require firms to provide each consumer with information about her own usage of the firm's product.
Mullainathan, Sendhil, Jens Ludwig, and Jeffrey R Kling. 2011. “Mechanism Experiments and Policy Evaluations.” Journal of Economic Perspectives 25 (3): 17-38.Abstract
Randomized controlled trials are increasingly used to evaluate policies. How can we make these experiments as useful as possible for policy purposes? We rgue greater use should be made of experiments that identify behavioral mechanisms that are central to clearly specified policy questions, what we call “mechanism experiments.” These types of experiments can be of great policy value even if the intervention that is tested (or its setting) does not correspond exactly to any realistic policy option.
David, Abrams, Bertrand Marianne, and Mullainathan Sendhil. 2011. “Do Judges Vary in Their Treatment of Race?.” Journal of Legal Studies.Abstract
Are minorities treated differently by the legal system? Systematic racial differences in case characteristics, many unobservable, make this a difficult question to answer directly. In this paper, we estimate whether judges differ from each other in how they sentence minorities, avoiding potential bias from unobservable case characteristics by exploiting the random assignment of cases to judges. We measure the between-judge variation in the difference in incarceration rates and sentence lengths between African-American and White defendants. We perform a Monte Carlo simulation in order to explicitly construct the appropriate counterfactual, where race does not influence judicial sentencing. In our data set, which includes felony cases from Cook County, Illinois, we find statistically significant between-judge variation in incarceration rates, although not in sentence lengths.
Allcott, Hunt, Sendhil Mullainathan, and Dmitry Taubinsky. 2011. “Externalizing the internality”.Abstract
We use a theoretical model and empirically-calibrated simulations of the automobile market to show how the traditional logic of Pigouvian taxation changes when consumers are inattentive to energy costs. Under inattention, there is a "Triple Dividend" from externality taxes: aside from reducing the provision of public bads and generating government revenue, they also reduce allocative ine¢ ciencies caused by underinvestment in energy e¢ cient capital stock. While Pigouvian taxes are clearly the preferred policy mechanism when externalities are the only market failure, inattention provides an "Internality Rationale" for alternative policies such as subsidies that reduce the relative price of energy e¢ cient durable goods. However, heterogeneity in the way that consumers optimize or misoptimize means that non-discriminatory taxes and subsidies are blunt instruments for addressing misoptimization: any given policy is too strong for some consumers and too weak for others. We therefore discuss "Behavioral Targeting": the use of mechanisms such as tagging, screening, and nudges that preferentially a§ect misoptimizers. We also formally deÖne a class of mechanisms called "Nudge-Inducing Policies," which are taxes speciÖcally designed to encourage Örms to use advertising, information provision, retail sales interactions, and other nudges to debias misoptimizing consumers.
Mullainathan, Sendhil, Ebonya Washington, and Julia R Azari. 2010. “The Impact of Electoral Debate on Public Opinion: An Experimental Investigation of the 2005 New York City Mayoral Election.” Political Representation, edited by Ian Shapiro, Stokes C Susan, Wood Elisabeth Jean, and Kirshner S Alexander, 324-342. Cambridge University Press, 324-342.
Mullainathan, Sendhil, and Philipp Schnabl. 2010. “Does Less Market Entry Regulation Generate More Entrepreneurs? Evidence from a Regulatory Reform in Peru.” International Differences in Entrepreneurship, edited by Lerner Josh and Schoar Antoinette, 159-179. University of Chicago Press, 159-179. does_less_market_entry_regulation_generate_more_entrepreneurs_evidence_from_a_regulatory_reform_in_peru.pdf
Bertrand, M, D Karlan, S Mullainathan, E Shafir, and J Zinman. 2010. “What’s Advertising Content Worth? Evidence from a Consumer Credit Marketing Field Experiment.” The Quarterly Journal of Economics 125 (1): 263–305.Abstract
Firms spend billions of dollars developing advertising content, yet there is little field evidence on how much or how it affects demand. We analyze a direct mail field experiment in South Africa implemented by a consumer lender that randomized advertising content, loan price, and loan offer deadlines simultaneously. We find that advertising content significantly affects demand. Although it was difficult to predict exante which specific advertising features would matter most in this context, the features that do matter have large effects. Showing fewer example loans, not suggesting a particular use for the loan, or including a photo of an attractive female increase loan demand by about as much as a 25% reduction in the interest rate. The evidence also suggests that advertising content persuades by appealing "peripherally": to intuition rather than reason. Although the advertising content effects point to an important role for persuasion and related psychology, our deadline results do not support the psychological prediction that shorter deadlines may help overcome time-management problems; instead, demand strongly increases with longer deadlines