Knowledge that Transforms

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Naïveté-Based Discrimination*

Quarterly Journal of Economics 2017 132(2), 1019-1054 open access
We initiate the study of naïveté-based discrimination, the practice of conditioning offers on external information about consumers’ naïveté. Knowing that a consumer is naive increases a monopolistic or competitive firm's willingness to generate inefficiency to exploit the consumer's mistakes, so naïveté-based discrimination is not Pareto-improving, can be Pareto-damaging, and often lowers total welfare when classical preference-based discrimination does not. Moreover, the effect on total welfare depends on a hitherto unemphasized market feature: the extent to which the exploitation of naive consumers distorts trade with different types of consumers. If the distortion is homogeneous across naive and sophisticated consumers, then under an arguably weak and empirically testable condition, naïveté-based discrimination lowers total welfare. In contrast, if the distortion arises only for trades with sophisticated consumers, then perfect naïveté-based discrimination maximizes social welfare, although imperfect discrimination often lowers welfare. If the distortion arises only for trades with naive consumers, then naïveté-based discrimination has no effect on welfare. We identify applications for each of these cases. In our primary example, a credit market with present-biased borrowers, firms lend more than is socially optimal to increase the amount of interest naive borrowers unexpectedly pay, creating a homogeneous distortion. The condition for naïveté-based discrimination to lower welfare is then weaker than prudence.

Uncertainty Traps*

Quarterly Journal of Economics 2017 132(4), 1641-1692
We develop a theory of endogenous uncertainty and business cycles in which short-lived shocks can generate long-lasting recessions. In the model, higher uncertainty about fundamentals discourages investment. Since agents learn from the actions of others, information flows slowly in times of low activity and uncertainty remains high, further discouraging investment. The economy displays uncertainty traps: self-reinforcing episodes of high uncertainty and low activity. Although the economy recovers quickly after small shocks, large temporary shocks may have long-lasting effects on the level of activity. The economy is subject to an information externality but uncertainty traps may remain in the efficient allocation. Embedding the mechanism in a standard business cycle framework, we find that endogenous uncertainty increases the persistence of large recessions and improves the performance of the model in accounting for the Great Recession.

Credit Crises, Precautionary Savings, and the Liquidity Trap*

Quarterly Journal of Economics 2017 132(3), 1427-1467
We study the effects of a credit crunch on consumer spending in a heterogeneous-agent incomplete-market model. After an unexpected permanent tightening in consumers’ borrowing capacity, constrained consumers are forced to repay their debt, and unconstrained consumers increase their precautionary savings. This depresses interest rates, especially in the short run, and generates an output drop, even with flexible prices. The output drop is larger with sticky prices, if the zero lower bound prevents the interest rate from adjusting downward. Adding durable goods to the model, households take larger debt positions and the output response can be larger.

Who Becomes A Politician?*

Quarterly Journal of Economics 2017 132(4), 1877-1914 open access
Can a democracy attract competent leaders, while attaining broad representation? Economic models suggest that free-riding incentives and lower opportunity costs give the less competent a comparative advantage at entering political life. Moreover, if elites have more human capital, selecting on competence may lead to uneven representation. This article examines patterns of political selection among the universe of municipal politicians and national legislators in Sweden, using extraordinarily rich data on competence traits and social background for the entire population. We document four new facts that together characterize an “inclusive meritocracy.” First, politicians are on average significantly smarter and better leaders than the population they represent. Second, this positive selection is present even when conditioning on family (and hence social) background, suggesting that individual competence is key for selection. Third, the representation of social background, whether measured by parental earnings or occupational social class, is remarkably even. Fourth, there is at best a weak trade-off in selection between competence and social representation, mainly due to strong positive selection of politicians of low (parental) socioeconomic status. A broad implication of these facts is that it is possible for democracy to generate competent and socially representative leadership.

Choose to Lose: Health Plan Choices from a Menu with Dominated Option*

Quarterly Journal of Economics 2017 132(3), 1319-1372
We examine the health plan choices that 23,894 employees at a U.S. firm made from a large menu of options that differed only in financial cost-sharing and premium. These decisions provide a clear test of the predictions of the standard economic model of insurance choice in the absence of choice frictions because plans were priced so that nearly every plan with a lower deductible was financially dominated by an otherwise identical plan with a high deductible. We document that the majority of employees chose dominated plans, which resulted in excess spending equivalent to 24% of chosen plan premiums. Low-income employees were significantly more likely to choose dominated plans, and most employees did not switch into more financially efficient plans in the subsequent year. We show that the choice of dominated plans cannot be rationalized by standard risk preference or any expectations about health risk. Testing alternative explanations with a series of hypothetical-choice experiments, we find that the popularity of dominated plans was not primarily driven by the size and complexity of the plan menu, nor informed preferences for avoiding high deductibles, but by employees’ lack of understanding of health insurance. Our findings challenge the standard practice of inferring risk preferences from insurance choices and raise doubts about the welfare benefits of health reforms that expand consumer choice.

What is the Expected Return on the Market?*

Quarterly Journal of Economics 2017 132(1), 367-433 open access
I derive a lower bound on the equity premium in terms of a volatility index, SVIX, that can be calculated from index option prices. The bound implies that the equity premium is extremely volatile and that it rose above 20% at the height of the crisis in 2008. The time-series average of the lower bound is about 5%, suggesting that the bound may be approximately tight. I run predictive regressions and find that this hypothesis is not rejected by the data, so I use the SVIX index as a proxy for the equity premium and argue that the high equity premia available at times of stress largely reflect high expected returns over the very short run. I also provide a measure of the probability of a market crash, and introduce simple variance swaps, tradable contracts based on SVIX that are robust alternatives to variance swaps.

Lemon Technologies and Adoption: Measurement, Theory and Evidence from Agricultural Markets in Uganda*

Quarterly Journal of Economics 2017 132(3), 1055-1100 open access
To reduce poverty and food insecurity in Africa requires raising productivity in agriculture. Systematic use of fertilizer and hybrid seed is a pathway to increased productivity, but adoption of these technologies remains low. We investigate whether the quality of agricultural inputs can help explain low take-up. Testing modern products purchased in local markets, we find that 30% of nutrient is missing in fertilizer, and hybrid maize seed is estimated to contain less than 50% authentic seeds. We document that such low quality results in low average returns. If authentic technologies replaced these low-quality products, however, average returns are high. To rationalize the findings, we calibrate a learning model using data from our agricultural trials. Because agricultural yields are noisy, farmers’ ability to learn about quality is limited and this can help explain the low quality equilibrium we observe, but also why the market has not fully collapsed.

Party Polarization in Legislatures with Office-Motivated Candidates*

Quarterly Journal of Economics 2017 132(3), 1509-1550
We develop a theory of legislative competition in which voters care about local candidate valence and national party positions that are determined by the parties’ median legislators. As long as election outcomes are sufficiently predictable, the only stable equilibria exhibit policy divergence between the parties. If the degree of uncertainty about election outcomes decreases, and if voters place less weight on local candidates’ valence, polarization between the parties increases. Furthermore, a systematic electoral shock makes the party favored by the shock more moderate, while the disadvantaged party becomes more extreme. Finally, we examine data on state elections and the ideological positions of state legislatures and find patterns that are consistent with key predictions of our model.

News Shocks in Open Economies: Evidence from Giant Oil Discoveries*

Quarterly Journal of Economics 2017 132(1), 103-155 open access
This article explores the effect of news shocks in open economies using worldwide giant oil and gas discoveries as a directly observable measure of news shocks about future output—the delay between a discovery and production is on average four to six years. We first analyze the effects of a discovery in a two-sector small open economy model with a resource sector. We then estimate the effects of giant oil and gas discoveries on a large panel of countries. Our empirical estimates are consistent with the predictions of the model. After an oil or gas discovery, the current account and saving rate decline for the first five years and then rise sharply during the ensuing years. Investment rises robustly soon after the news arrives, whereas GDP does not increase until after five years. Employment rates fall slightly and remain low for a sustained period.

Reference-Dependent Job Search: Evidence from Hungary*

Quarterly Journal of Economics 2017 132(4), 1969-2018
We propose a model of job search with reference-dependent preferences, with loss aversion relative to recent income (the reference point). In this model, newly unemployed individuals search hard since consumption is below their reference point. Over time, though, they get used to lower income and thus reduce their search effort. In anticipation of a benefit cut, their search effort rises again, then declines once they get accustomed to the lower postcut benefit level. The model fits the typical pattern of exit from unemployment, even with no unobserved heterogeneity. To distinguish between this and other models, we use a unique reform in the unemployment insurance (UI) benefit path. In 2005, Hungary switched from a single-step UI system to a two-step system, with overall generosity unchanged. The system generated increased hazard rates in anticipation of, and especially following, benefit cuts in ways the standard model has a hard time explaining. We estimate a model with optimal consumption, endogenous search effort, and unobserved heterogeneity. The reference-dependent model fits the hazard rates substantially better than plausible versions of the standard model, including habit formation. Our estimates indicate a slow-adjusting reference point and substantial impatience, likely reflecting present-bias.