This essay reviews new histories of the role of game theory and rational decision making in shaping the social sciences, economics among them, in the postwar period. The recent books The World the Game Theorists Made by Paul Erickson and How Reason Almost Lost Its Mind: The Strange Career of Cold War Rationality by Paul Erickson, Judy Klein, Lorraine Daston, Rebecca Lemov, Thomas Sturm, and Michael Gordin raise a number of complex historical questions about the interconnections among game theory, utility theory, decision theory, optimization theory, information theory, and theories of rational choice. Moreover, the contingencies of time, place, and person call into question the usefulness of economists' linear narratives about the autonomous and progressive development of modern economics. The essay finally reflects on the challenges that these issues present for historians of recent economics.

This essay compares the Great Depression to the Great Recession in light of Barry Eichengreen's new book Hall of Mirrors. Eichengreen discusses these two episodes from a historical, Keynesian perspective, and concludes that policies that increase aggregate demand, such as larger fiscal deficits, would have promoted a much stronger and faster recovery from the Great Recession. I review these episodes from a neoclassical approach, which provides a very different perspective on why recoveries from these episodes were so slow and incomplete. I also argue that supply-side policies, rather than demand-side policies, are more likely to restore prosperity today.

Conditional cash transfer (CCT) programs innovate by conditioning transfers to poor families on investments in the human capital of children and other family members. The Mexican CCT program Progresa/Oportunidades began in 1997 and has served as a model for many of the now over sixty countries with CCTs around the world, in large part due to its initial evaluation with an experimental design and numerous follow-up studies. This article reviews the literature on the development, evaluation, and findings of Progresa/Oportunidades, summarizing what is known about program effects, taking into account corrections for multiple-hypothesis testing.

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.