We develop an endogenous growth model in which clean and dirty technologies compete in production. Research can be directed to either technology. If dirty technologies are more advanced, the transition to clean technology can be difficult. Carbon taxes and research subsidies may encourage production and innovation in clean technologies, though the transition will typically be slow. We estimate the model using microdata from the US energy sector. We then characterize the optimal policy path that heavily relies on both subsidies and taxes. Finally, we evaluate various alternative policies. Relying only on carbon taxes or delaying intervention has significant welfare costs.

Even before the Great Recession, US employment growth was unimpressive. Between 2000 and 2007, the economy gave back the considerable employment gains achieved during the 1990s, with a historic contraction in manufacturing employment being a prime contributor to the slump. We estimate that import competition from China, which surged after 2000, was a major force behind both recent reductions in US manufacturing employment and—through input-output linkages and other general equilibrium channels—weak overall US job growth. Our central estimates suggest job losses from rising Chinese import competition over 1999–2011 in the range of 2.0–2.4 million.

Existing studies establish a strong cross-country correlation between income and democracy but do not control for factors that simultaneously affect both variables. We show that controlling for such factors by including country fixed effects removes the statistical association between income per capita and various measures of democracy. We present instrumental-variables estimates that also show no causal effect of income on democracy. The cross-country correlation between income and democracy reflects a positive correlation between changes in income and democracy over the past 500 years. This pattern is consistent with the idea that societies embarked on divergent political-economic development paths at certain critical junctures.

The conventional wisdom views high levels of education as a prerequisite for democracy. This paper shows that existing evidence for this view is based on crosssectional correlations, which disappear once we look at within-country variation. In other words, there is no evidence that countries that increase their education are more likely to become democratic.

We provide evidence that democracy has a positive effect on GDP per capita. Our dynamic panel strategy controls for country fixed effects and the rich dynamics of GDP, which otherwise confound the effect of democracy. To reduce measurement error, we introduce a new indicator of democracy that consolidates previous measures. Our baseline results show that democratizations increase GDP per capita by about 20 percent in the long run. We find similar effects using a propensity score reweighting strategy as well as an instrumental-variables strategy using regional waves of democratization. The effects are similar across different levels of development and appear to be driven by greater investments in capital, schooling, and health.

This paper develops a model of Bayesian learning from online reviews and investigates the conditions for learning the quality of a product and the speed of learning under different rating systems. A rating system provides information about reviews left by previous customers. observe the ratings of a product and decide whether to purchase and review it. We study learning dynamics under two classes of rating systems: full history , where customers see the full history of reviews, and summary statistics , where the platform reports some summary statistics of past reviews. In both cases, learning dynamics are complicated by a selection effect —the types of users who purchase the good, and thus their overall satisfaction and reviews depend on the information available at the time of purchase. We provide conditions for complete learning and characterize and compare its speed under full history and summary statistics. We also show that providing more information does not always lead to faster learning, but strictly finer rating systems do.

This paper argues that in the presence of intersectoral input-output linkages, microeconomic idiosyncratic shocks may lead to aggregate fluctuations.We show, as the economy becomes more disaggregated, the rate at which aggregate volatility decays is determined by the structure of the network capturing such linkages.Our main results provide a characterization of this relationship in terms of the importance of different sectors as suppliers to their immediate customers as well as their role as indirect suppliers to chains of downstream sectors.Such higher-order interconnections capture the possibility of "cascade effects" whereby productivity shocks to a sector propagate not only to its immediate downstream customers, but also to the rest of the economy.Our results highlight that sizable aggregate volatility is obtained from sectoral idiosyncratic shocks only if there exists significant asymmetry in the roles that sectors play as suppliers to others, and that the "sparseness" of the input-output matrix is unrelated to the nature of aggregate fluctuations.

The introduction of Medicare in 1965 was the single largest change in health insurance coverage in U.S. history.Many economists and commentators have conjectured that the introduction of Medicare may have also been an important impetus for the development of new drugs that are now commonly used by the elderly and have substantially extended their life expectancy.In this paper, we investigate whether Medicare induced pharmaceutical innovations directed towards the elderly.Medicare could have played such a role only if two conditions were met.First, Medicare would have to increase drug spending by the elderly.Second, the pharmaceutical companies would have to respond to the change in market size for drugs caused by Medicare by changing the direction of their research.Our empirical work finds no evidence of a "first-stage" effect of Medicare on prescription drug expenditure by the elderly.Correspondingly, we also find no evidence of a shift in pharmaceutical innovation towards therapeutic categories most used by the elderly.On the whole, therefore, our evidence does not provide support for the hypothesis that Medicare had a major effect on the direction of pharmaceutical innovation.

The French Revolution had a momentous impact on neighboring countries. It removed the legal and economic barriers protecting oligarchies, established the principle of equality before the law, and prepared economies for the new industrial opportunities of the second half of the 19th century. We present within-Germany evidence on the long-run implications of these institutional reforms. Occupied areas appear to have experienced more rapid urbanization growth, especially after 1850. A two-stage least squares strategy provides evidence consistent with the hypothesis that the reforms instigated by the French had a positive impact on growth. JEL: N13, N43, O47