The Role of Randomized Field Trials in Social Science Research: A Perspective from Evaluations of Reforms of Social Welfare Programs

One of the areas of policy research where randomized field trials have been utilized most intensively is welfare reform. Starting in the late 1960s with experimental tests of a negative income tax and continuing through current experimental tests of recent welfare reforms, randomized evaluations have played a strong and increasing role in informing policy. This paper reviews the record of these experiments and assesses the implications of that record for the use of randomization. The review demonstrates that, while randomized field trials in the area of welfare reform have been professionally conducted and well-run, and have yielded much valuable and credible information, their usefulness has been limited by a number of weaknesses, some of which are inherent in the method and some of which result from constraints imposed by the political process. The conclusion is that randomized field trials have an important but limited role to play in future welfare reform evaluations, and that it is essential that they be supplemented by nonexperimental research.

Water Quality Trading Programs: An International Overview

Explains water quality trading, in which nutrient discharges in waterways are capped and high polluters can purchase pollution discharge credits from others. Compares programs and discusses program design, costs, elements of success, and lessons learned

Getting Back in the Black

Details the commission's medium- and long-term recommendations for reforming the federal budget process and stabilizing the debt, including a Sustainable Debt Act, a credible multiyear budget plan, strong enforcement mechanisms, and greater transparency

Reducing Revenue to Welfare Maximization: Approximation Algorithms and other Generalizations

It was recently shown in [http://arxiv.org/abs/1207.5518] that revenue optimization can be computationally efficiently reduced to welfare optimization in all multi-dimensional Bayesian auction problems with arbitrary (possibly combinatorial) feasibility constraints and independent additive bidders with arbitrary (possibly combinatorial) demand constraints. This reduction provides a poly-time solution to the optimal mechanism design problem in all auction settings where welfare optimization can be solved efficiently, but it is fragile to approximation and cannot provide solutions to settings where welfare maximization can only be tractably approximated. In this paper, we extend the reduction to accommodate approximation algorithms, providing an approximation preserving reduction from (truthful) revenue maximization to (not necessarily truthful) welfare maximization. The mechanisms output by our reduction choose allocations via black-box calls to welfare approximation on randomly selected inputs, thereby generalizing also our earlier structural results on optimal multi-dimensional mechanisms to approximately optimal mechanisms. Unlike [http://arxiv.org/abs/1207.5518], our results here are obtained through novel uses of the Ellipsoid algorithm and other optimization techniques over {\em non-convex regions}

Separating Two-Round Secure Computation From Oblivious Transfer

We consider the question of minimizing the round complexity of protocols for secure multiparty computation (MPC) with security against an arbitrary number of semi-honest parties. Very recently, Garg and Srinivasan (Eurocrypt 2018) and Benhamouda and Lin (Eurocrypt 2018) constructed such 2-round MPC protocols from minimal assumptions. This was done by showing a round preserving reduction to the task of secure 2-party computation of the oblivious transfer functionality (OT). These constructions made a novel non-black-box use of the underlying OT protocol. The question remained whether this can be done by only making black-box use of 2-round OT. This is of theoretical and potentially also practical value as black-box use of primitives tends to lead to more efficient constructions. Our main result proves that such a black-box construction is impossible, namely that non-black-box use of OT is necessary. As a corollary, a similar separation holds when starting with any 2-party functionality other than OT. As a secondary contribution, we prove several additional results that further clarify the landscape of black-box MPC with minimal interaction. In particular, we complement the separation from 2-party functionalities by presenting a complete 4-party functionality, give evidence for the difficulty of ruling out a complete 3-party functionality and for the difficulty of ruling out black-box constructions of 3-round MPC from 2-round OT, and separate a relaxed "non-compact" variant of 2-party homomorphic secret sharing from 2-round OT

Reconstructing Climate Policy: Beyond Kyoto

In their comprehensive analysis of the Kyoto Protocol and climate policy, Richard B. Stewart and Jonathan B. Wiener examine the current impasse in climate policy and the potential steps nations can take to reduce greenhouse gases. They summarize the current state of information regarding the extent of global warming that would be caused by increasing uncontrolled greenhouse gas emissions. They explain why participation by all major greenhouse gas-emitting countries is essential to curb future greenhouse gas emissions and also note the significant obstacles to obtaining such participation. Stewart and Wiener argue it is in the national interest of the United States to participate in such a regime, provided that it is well designed. They discuss the elements of sound climate regulatory design, including maximum use of economic incentives, the comprehensive approach, and other flexibility mechanisms; participation by all major emitting countries, including developing countries; regulatory targets based on longer-term emissions pathways set to maximize net social benefits; and effective arrangements to ensure compliance with regulatory obligations by nations and sources. After evaluating the successes and failures of the Kyoto Protocol in light of those elements, the authors propose a series of U.S. initiatives at the international and domestic levels, with the aim of engaging the United States and major developing country emitters such as China in the global greenhouse gas regulatory effort and correcting the remaining defects in the design of the Kyoto Protocol. Although several alternatives to the current Kyoto Protocol regime have been proposed, Stewart and Wiener argue that the best approach for surmounting the current global climate policy impasse is a new strategy that would lead, sooner or later, to simultaneous accession by the United States and China (and other major developing country emitters) to a modified and improved version of the Kyoto Protocol agreement

Reconstructing Climate Policy: Beyond Kyoto

In their comprehensive analysis of the Kyoto Protocol and climate policy, Richard B. Stewart and Jonathan B. Wiener examine the current impasse in climate policy and the potential steps nations can take to reduce greenhouse gases. They summarize the current state of information regarding the extent of global warming that would be caused by increasing uncontrolled greenhouse gas emissions. They explain why participation by all major greenhouse gas-emitting countries is essential to curb future greenhouse gas emissions and also note the significant obstacles to obtaining such participation. Stewart and Wiener argue it is in the national interest of the United States to participate in such a regime, provided that it is well designed. They discuss the elements of sound climate regulatory design, including maximum use of economic incentives, the comprehensive approach, and other flexibility mechanisms; participation by all major emitting countries, including developing countries; regulatory targets based on longer-term emissions pathways set to maximize net social benefits; and effective arrangements to ensure compliance with regulatory obligations by nations and sources. After evaluating the successes and failures of the Kyoto Protocol in light of those elements, the authors propose a series of U.S. initiatives at the international and domestic levels, with the aim of engaging the United States and major developing country emitters such as China in the global greenhouse gas regulatory effort and correcting the remaining defects in the design of the Kyoto Protocol. Although several alternatives to the current Kyoto Protocol regime have been proposed, Stewart and Wiener argue that the best approach for surmounting the current global climate policy impasse is a new strategy that would lead, sooner or later, to simultaneous accession by the United States and China (and other major developing country emitters) to a modified and improved version of the Kyoto Protocol agreement