The science of economics has some constraints and tensions that set it apart from other sciences. One reflection of these constraints and tensions is that, more than in most other scientific disciplines, it is easy to find economists of high reputation who disagree strongly with one another on issues of wide public interest. This may sug gest that economics, unlike most other scientific disciplines, does not really make progress. Its theories and results seem to come and go, always in hot dispute, rather than improving over time so as to build an increasing body of knowledge. There is some truth to this view; there are examples where disputes of earlier decades have been not so much resolved as replaced by new disputes. But though econom ics progresses unevenly, and not even monotonically, there are some examples of real scientific progress in economics. This essay describes one—the evolution since around 1950 of our understanding of how monetary policy is determined and what its effects are. The story described here is not a simple success story. It describes an ascent to higher ground, but the ground is still shaky. Part of the purpose of the essay is to remind readers of how views strongly held in earlier decades have since been shown to be mistaken. This should encourage continuing skepticism of consensus views and motivate critics to sharpen their efforts at looking at new data, or at old data in new ways, and generating improved theories in the light of what they see. We will be tracking two interrelated strands of intellectual effort: the methodol ogy of modeling and inference for economic time series, and the theory of policy influences on business cycle fluctuations. The starting point in the 1950s of the the ory of macroeconomic policy was Keynes's analysis of the Great Depression of the 1930s, which included an attack on the Quantity Theory of money. In the 1930s, interest rates on safe assets had been at approximately zero over long spans of time, and Keynes explained why, under these circumstances, expansion of the money sup ply was likely to have little effect. The leading American Keynesian, Alvin Hansen, included in his (1952) book A Guide to Keynes a chapter on money, in which he explained Keynes's argument for the likely ineffectiveness of monetary expansion in a period of depressed output. Hansen concluded the chapter with, Thus it is that modern countries place primary emphasis on fiscal policy, in whose service mone tary policy is relegated to the subsidiary role of a useful but necessary handmaiden. The methodology of modeling in the 1950s built on Jan Tinbergen's (1939) seminal book, which presented probably the first multiple-equation, statistically estimated economic time series model. His efforts drew heavy criticism. Keynes

In spite of the common wisdom that poverty breeds terrorism, econometric tests usually find that terrorism is influenced by population and various measures of democratic freedom, but not per capita GDP. Unlike previous studies, we use a data set containing separate measures of domestic and transnational terrorism and estimate models allowing for a nonlinear relationship between terrorism and poverty. When we account for the nonlinearities in the data and distinguish between the two types of terrorist events, we find that poverty has as a very strong influence on domestic terrorism and a small, but significant, effect on transnational terrorism.

From Fred Kahn's writings and experiences as a telecommunications regulator and commenter, we draw the following conclusions: prices must be informed by costs; costs are actual incremental costs; costs and prices are an outcome of a Schumpeterian competitive process, not the starting point; excluding incumbents from markets is fundamentally anticompetitive; and a regulatory transition to deregulation entails propensities to micromanage the process to generate preferred outcomes, visible competitors and expedient price reductions. And most important, where effective competition takes place among platforms characterized by sunk investment—land-line telephony, cable and wireless —traditional regulation is unnecessary and likely to be anticompetitive.

The article develops a new theory of pricing to market driven by dynamic frictions of building market shares. Our key innovation is a capital theoretic model of marketing in which relations with customers are valuable. We discipline the introduced friction using data on differences between short-run and long-run price elasticity of international trade flows. We show that the model accounts for several pricing “puzzles” of international macroeconomics. (JEL E13, F14, F31, F41, F44, M31)

This short paper examines the effect of exporting on within-plant wage distributions in employer-employee data on Mexican manufacturing plants. Using the late-1994 peso devaluation interacted with initial plant size as a source of exogenous variation in exporting and focusing on wages at the 10th, 25th, 50th, 75th and 90th percentiles within each plant, we document three patterns: (1) there is no evidence of an effect of exporting on wages at the 10th percentile; (2) the wage effects of exporting are larger at higher percentiles, up to the 75th; and (3) there is no evidence of an increase in dispersion within the top quartile.

Many business cycle models use a flat short-run Phillips curve, due to time-dependent pricing and strategic complementarities, to explain fluctuations in real output. But, in doing so, these models predict unrealistically high persistence and stability of US inflation in recent decades. We calculate “reset price inflation”—based on new prices chosen by the subsample of price changers—to dissect this discrepancy. We find that the models generate too much persistence and stability both in reset price inflation and in the way reset price inflation is converted into actual inflation. Our findings present a challenge to existing explanations for business cycles. (JEL E31, E52)

During recessions, the focus on male job losses may overshadow other important outcome variables. We examine the effects of economic downturns on occupational segregation by gender, using staffing data from over 6 million private-sector US establishments from 1966-2010. Consistent with the literature, we find a downward trend in occupational segregation that is diminishing over time. Drawing upon Rubery's (1988) work on women and recessions, we find support for both the buffer and the segmentation hypotheses. On net, however, the buffer hypothesis appears to dominate providing evidence that in periods of economic decline the trend of decreasing economic dissimilarity is interrupted.

It is widely recognized that the 2006 Massachusetts health reforms served as a blueprint for national reform under the 2010 Affordable Care Act (ACA). As such, there is interest in using the Massachusetts experience to understand how insurance premiums might change under the ACA. In this paper, we analyze changes in private insurance premiums in Massachusetts between 2002 and 2010. In contrast to earlier estimates from Massachusetts (Cogan, Hubbard and Kessler 2010), we find no statistical evidence of changes in group premiums. By contrast, we find large reductions in non-group premiums in Massachusetts relative to the rest of the U.S.

The financial industry relies on trade secrecy to protect its business processes and methods, which can obscure critical financial risk exposures from regulators and the public. Using results from cryptography, we develop computationally tractable protocols for sharing and aggregating such risk exposures that protect the privacy of all parties involved, without the need for trusted third parties. Financial institutions can share aggregate statistics such as Herfindahl indexes, variances, and correlations without revealing proprietary data. Potential applications include: privacy-preserving real-time indexes of bank capital and leverage ratios; monitoring delegated portfolio investments; financial audits; and public indexes of proprietary trading strategies.

This study estimates the effects of means-tested housing programs on labor supply using data from a randomized housing voucher wait-list lottery in Chicago. Economic theory is ambiguous about the expected sign of any labor supply response. We find that among working-age, able-bodied adults, housing voucher use reduces labor force participation by around 4 percentage points (6 percent) and quarterly earnings by $329 (10 percent), and increases Temporary Assistance for Needy Families program participation by around 2 percentage points (15 percent). We find no evidence that the housing-specific mechanisms hypothesized to promote work, such as neighborhood quality or residential stability, are important empirically. (JEL I38, J22, R23, R38)