Organizations & Markets

Particle learning (PL) provides state filtering, sequential parameter learning and smoothing in a general class of state space models. Our approach extends existing particle methods by incorporating the estimation of static parameters via a fully-adapted filter that utilizes conditional sufficient statistics for parameters and/or states as particles. State smoothing in the presence of parameter uncertainty is also solved as a by-product of PL. In a number of examples, we show that PL outperforms existing particle filtering alternatives and proves to be a competitor to MCMC.

The conventional wisdom is that politicians' rent-seeking motives increase public debt and deficits. This is because myopic politicians face political risk and prefer to extract political rents as early as possible. In this paper we study the determination of government debt and deficits in a dynamic political economy model. We show that this conventional wisdom relies on economic volatility being low relative to political uncertainty.

Using micro data on virtually all of the drugs and diseases of over 500,000 people enrolled in Puerto Rico's Medicaid program, the impact of the vintage (original FDA approval year) of drugs used to treat a patient on the patient's three-year probability of survival, controlling for demographic characteristics (age, sex, and region), utilization of medical services, and the nature and complexity of illness are examined. It is found that people using newer drugs during January-June, 2000, were less likely to die by the end of 2002, conditional on the covariates.

Teaching may be the most-scrutinized occupation in the economy. Over the past four decades, empirical researchers—many of them economists—have accumulated an impressive amount of evidence on teachers: the heterogeneity in teacher productivity, the rise in productivity associated with teaching credentials and on-the-job experience, rates of turnover, the costs of recruitment, the relationship between supply and quality, the effect of class size and the monetary value of academic achievement gains over a student's lifetime.

I examine the impact of a property tax relief program in New York State that lowered the marginal cost of school expenditure to homeowners. I find that a typical school district, which received 20% of its revenue through the program in the school year 2001–2002, raised expenditure by 4.1% and local property taxes by 6.8% in response to the program. I then examine how the preferences of various groups of local taxpayers affect educational spending by identifying systematic variation across districts in the response to fiscal incentives.

Prices are typically used as proxies for countries' export quality. I relax this strong assumption by exploiting both price and quantity information to estimate the quality of products exported to the U.S. Higher quality is assigned to products with higher market shares conditional on price. The estimated qualities reveal substantial heterogeneity in product markets' scope for quality differentiation, or their "quality ladders." I use this variation to explain the heterogeneous impact of low-wage competition on U.S. manufacturing employment and output.

In every period, an aggressive country seeks concessions from a non-aggressive country with private information about their cost. The aggressive country can force concessions via war, and both countries suffer from limited commitment.We characterize the efficient sequential equilibria. We show that war is necessary to sustain peace and that temporary wars can emerge because of the coarseness of public information. In the long run, temporary wars can be sustained only if countries are patient, if the cost of war is large, and if the cost of concessions is low.

The preferred risk habitat hypothesis, introduced here, is that individual investors select stocks whose volatilities are commensurate with their risk aversion. The data, 1995-2000 holdings of over 20,000 clients at a large German broker, are consistent with the predictions of the hypothesis: the portfolios contain highly similar stocks in terms of volatility, when stocks are sold they are replaced by stocks of similar volatilities, and the more risk averse customers indeed hold and trade into less volatile stocks.

New goods play a central role in many trade and growth models. We use detailed trade and firm-level data from India to investigate the relationship between declines in trade costs, imports of intermediate inputs and domestic firm product scope. We estimate substantial gains from trade through access to new imported inputs. Moreover, we find that lower input tariffs account on average for 31 percent of the new products introduced by domestic firms.