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作者：Nunn, Nathan; Qian, Nancy
作者单位：Harvard University; National Bureau of Economic Research; Yale University
摘要：We exploit regional variation in suitability for cultivating potatoes, together with time variation arising from their introduction to the Old World from the Americas, to estimate the impact of potatoes on Old World population and urbanization. Our results show that the introduction of the potato was responsible for a significant portion of the increase in population and urbanization observed during the eighteenth and nineteenth centuries. According to our most conservative estimates, the intr...
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作者：Gentzkow, Matthew; Shapiro, Jesse M.
作者单位：National Bureau of Economic Research
摘要：We use individual and aggregate data to ask how the Internet is changing the ideological segregation of the American electorate. Focusing on online news consumption, offline news consumption, and face-to-face social interactions, we define ideological segregation in each domain using standard indices from the literature on racial segregation. We find that ideological segregation of online news consumption is low in absolute terms, higher than the segregation of most offline news consumption, a...
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作者：Jayachandran, Seema; Kuziemko, Ilyana
作者单位：Northwestern University; National Bureau of Economic Research; Princeton University
摘要：Breastfeeding is negatively correlated with future fertility because nursing temporarily reduces fecundity and because mothers usually wean on becoming pregnant again. We model breastfeeding under son-biased fertility preferences and show that breastfeeding duration increases with birth order, especially near target family size; is lowest for daughters and children without older brothers because their parents try again for a son; and exhibits the largest gender gap near target family size, whe...
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作者：Barro, Robert J.; Redlick, Charles J.
作者单位：Harvard University
摘要：For U.S. annual data that include World War II, the estimated multiplier for temporary defense spending is 0.4-0.5 contemporaneously and 0.6-0.7 over 2 years. If the change in defense spending is permanent (gauged by Ramey's defense news variable), the multipliers are higher by 0.1-0.2. Since all estimated multipliers are significantly less than 1, greater spending crowds out other components of GDP, particularly investment. The lack of good instruments prevents estimation of reliable multipli...
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作者：Fryer, Roland G., Jr.
作者单位：Harvard University; National Bureau of Economic Research
摘要：This article describes a series of school-based field experiments in over 200 urban schools across three cities designed to better understand the impact of financial incentives on student achievement. In Dallas, students were paid to read books. In New York, students were rewarded for performance on interim assessments. In Chicago, students were paid for classroom grades. I estimate that the impact of financial incentives on student achievement is statistically 0, in each city. Due to a lack o...
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作者：Hallak, Juan Carlos; Schott, Peter K.
作者单位：Universidad Mayor de San Andres; National Bureau of Economic Research; Yale University
摘要：We develop a method for decomposing countries' observed export prices into quality versus quality-adjusted components using information contained in trade balances. Holding observed export prices constant, countries with trade surpluses are inferred to offer higher quality than countries running trade deficits. We account for variation in trade balances induced by horizontal and vertical differentiation, and we estimate the evolution of manufacturing quality for top exporters from 1989 to 2003...
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作者：Kremer, Michael; Leino, Jessica; Miguel, Edward; Zwane, Alix Peterson
作者单位：Harvard University; Brookings Institution; National Bureau of Economic Research; The World Bank; University of California System; University of California Berkeley; Bill & Melinda Gates Foundation
摘要：Using a randomized evaluation in Kenya, we measure health impacts of spring protection, an investment that improves source water quality. We also estimate households' valuation of spring protection and simulate the welfare impacts of alternatives to the current system of common property rights in water, which limits incentives for private investment. Spring infrastructure investments reduce fecal contamination by 66%, but household water quality improves less, due to recontamination. Child dia...
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作者：Diermeier, Daniel; Fong, Pohan
摘要：We present a dynamic model of legislative bargaining with an endogenously evolving default policy and a persistent agenda setter. Policy making proceeds until the agenda setter can no longer pass a new policy to replace an approved bill. We prove existence and necessary conditions of pure-strategy stationary equilibria for any finite policy space, any number of players, and any preference profile. In equilibrium, the value of proposal power is limited compared to the case that disallows recons...
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作者：Ramey, Valerie A.
作者单位：University of California System; University of California San Diego; National Bureau of Economic Research
摘要：Standard vector autoregression (VAR) identification methods find that government spending raises consumption and real wages; the Ramey-Shapiro narrative approach finds the opposite. I show that a key difference in the approaches is the timing. Both professional forecasts and the narrative approach shocks Granger-cause the VAR shocks, implying that these shocks are missing the timing of the news. Motivated by the importance of measuring anticipations, I use a narrative method to construct riche...
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作者：Ericson, Keith M. Marzilli; Fuster, Andreas
作者单位：Harvard University
摘要：While evidence suggests that people evaluate outcomes with respect to reference points, little is known about what determines them. We conduct two experiments that show that reference points are determined, at least in part, by expectations. In an exchange experiment, we endow subjects with an item and randomize the probability they will be allowed to trade. Subjects that are less likely to be able to trade are more likely to choose to keep their item. In a valuation experiment, we randomly as...
