Knowledge that Transforms

We review the theoretical, computational, and empirical research on school vouchers, with a focus on the latter. Our assessment is that the evidence to date is not sufficient to warrant recommending that vouchers be adopted on a widespread basis; however, multiple positive findings support continued exploration. Specifically, the empirical research on small-scale programs does not suggest that awarding students a voucher is a systematically reliable way to improve educational outcomes, and some detrimental effects have been found. Nevertheless, in some settings, or for some subgroups or outcomes, vouchers can have a substantial positive effect on those who use them. Studies of large-scale voucher programs find student sorting as a result of their implementation, although of varying magnitude. Evidence on both small-scale and large-scale programs suggests that competition induced by vouchers leads public schools to improve. Moreover, research is making progress on understanding how vouchers may be designed to limit adverse effects from sorting, while preserving positive effects related to competition. Finally, our sense is that work originating in a single case (e.g., a given country) or in a single research approach (e.g., experimental designs) will not provide a full understanding of voucher effects; fairly wide-ranging empirical and theoretical work will be necessary to make progress. (JEL H52, H75, I21, I22, I28, O15)

We discuss the most popular static and dynamic models of household behavior. Our main objective is to explain which aspects of household decisions different models can account for. Using this insight, we describe testable implications, identification results, and estimation findings obtained in the literature. Particular attention is given to the ability of different models to answer various types of policy questions.

This essay surveys the new monetarist approach to liquidity. Work in this literature strives for empirical and policy relevance, plus rigorous foundations. Questions include: What is liquidity? Is money essential in achieving desirable outcomes? Which objects can or should serve in this capacity? When can asset prices differ from fundamentals? What are the functions of commitment and collateral in credit markets? How does money interact with credit and intermediation? What can and should monetary policy do? The research summarized emphasizes the micro structure of frictional transactions, and studies how institutions like monetary exchange, credit arrangements, or intermediation facilitate the exchange process. (JEL E24, E31, E42, E44, E52, G10, G21)

The United States has long been perceived as a land of opportunity for immigrants. Yet, both in the past and today, US natives have expressed concern that immigrants fail to integrate into US society and lower wages for existing workers. This paper reviews the literatures on historical and contemporary migrant flows, yielding new insights on migrant selection, assimilation of immigrants into US economy and society, and the effect of immigration on the labor market.

Energy-efficient technologies offer considerable promise for reducing the financial costs and environmental damages associated with energy use, but it has long been observed that these technologies may not be adopted by individuals and firms to the degree that might be justified, even on a purely financial basis. We survey the relevant literature on this “energy-efficiency gap” by presenting two complementary frameworks. First, we divide potential explanations for the energy-efficiency gap into three categories: market failures, behavioral explanations, and model and measurement errors. Second, we organize previous research in terms of the fundamental elements of cost-minimizing energy-efficiency decisions. This provides a decomposition that organizes thinking around four questions. First, are product offerings and pricing economically efficient? Second, are energy operating costs inefficiently priced and/or understood? Third, are product choices cost minimizing in present value terms? Fourth, do other costs inhibit more energy-efficient decisions? We synthesize academic research on these questions, with an emphasis on recent empirical findings, and offer suggestions for future research. (JEL D24, D82, L94, L98, O33, Q41, Q48)

We survey the literature on the economic consequences of the structure of social networks. We develop a taxonomy of “macro” and “micro” characteristics of social-interaction networks and discuss both the theoretical and empirical findings concerning the role of those characteristics in determining learning, diffusion, decisions, and resulting behaviors. We also discuss the challenges of accounting for the endogeneity of networks in assessing the relationship between the patterns of interactions and behaviors. (JEL D12, D83, D85, K42, Z13)

We review economics research regarding the effect of police, punishments, and work on crime, with a particular focus on papers from the last twenty years. Evidence in favor of deterrence effects is mixed. While there is considerable evidence that crime is responsive to police and to the existence of attractive legitimate labor-market opportunities, there is far less evidence that crime responds to the severity of criminal sanctions. We discuss fruitful directions for future work and implications for public policy. (JEL J64, K42)

We commonly think of information as a means to an end. However, a growing theoretical and experimental literature suggests that information may directly enter the agent's utility function. This can create an incentive to avoid information, even when it is useful, free, and independent of strategic considerations. We review research documenting the occurrence of information avoidance, as well as theoretical and empirical research on reasons why people avoid information, drawing from economics, psychology, and other disciplines. The review concludes with a discussion of some of the diverse (and often costly) individual and societal consequences of information avoidance. (JEL D82, D83)

Using Panel Study of Income Dynamics (PSID) microdata over the 1980–2010 period, we provide new empirical evidence on the extent of and trends in the gender wage gap, which declined considerably during this time. By 2010, conventional human capital variables taken together explained little of the gender wage gap, while gender differences in occupation and industry continued to be important. Moreover, the gender pay gap declined much more slowly at the top of the wage distribution than at the middle or bottom and by 2010 was noticeably higher at the top. We then survey the literature to identify what has been learned about the explanations for the gap. We conclude that many of the traditional explanations continue to have salience. Although human-capital factors are now relatively unimportant in the aggregate, women's work force interruptions and shorter hours remain significant in high-skilled occupations, possibly due to compensating differentials. Gender differences in occupations and industries, as well as differences in gender roles and the gender division of labor remain important, and research based on experimental evidence strongly suggests that discrimination cannot be discounted. Psychological attributes or noncognitive skills comprise one of the newer explanations for gender differences in outcomes. Our effort to assess the quantitative evidence on the importance of these factors suggests that they account for a small to moderate portion of the gender pay gap, considerably smaller than, say, occupation and industry effects, though they appear to modestly contribute to these differences. ( JEL I26, J16, J24, J31, J71)