Onsite concurrent review: impacts on utilization, medical complications and expense

An evaluation of onsite concurrent review over and above the effects of Aetna's precertification program demonstrated reduced utilization and expenses, especially for ancillary services, and no adverse effects on rates of medical complications.     

Hedonic models and air pollution: Twenty-five years and counting

This paper reports a meta analysis of how effectively hedonic property models have detected the influence of air pollution on housing prices. Probit estimates are reported describing how data, model specification, and local property market conditions in cities represented in thirty-seven studies influence the ability of hedonic models to uncover negative, statistically significant relationships between housing prices and air pollution measures.Partial support for this research was provided by the Russell Sage Foundation. Thanks are due David Cordray, Heidi Hartman, and Larry Hedges of the Foundation's Meta-Analysis Panel for constructive comments, to Ray Palmquist for suggestions and assistance in assembling the results from his studies, to Rick Freeman and Tom Tietenberg and two anonymous referees for comments on the research, and to Barbara Scott for constructive editing of earlier drafts of this paper.     

Strategic freedom, constraint, and symmetry in one-period markets with cash and credit payment

Summary. In order to explain in a systematic way why certain combinations of market, financial, and legal structures may be intrinsic to certain capabilities to exchange real goods, we introduce criteria for abstracting the qualitative functions of markets. The criteria involve the number of strategic freedoms the combined institutions, considered as formalized strategic games, present to traders, the constraints they impose, and the symmetry with which those constraints are applied to the traders. We pay particular attention to what is required to make these strategic market games well-defined, and to make various solutions computable by the agents within the bounds on information and control they are assumed to have. As an application of these criteria, we present a complete taxonomy of the minimal one-period exchange economies with symmetric information and inside money. A natural hierarchy of market forms is observed to emerge, in which institutionally simpler markets are often found to be more suitable to fewer and less-diversified traders, while the institutionally richer markets only become functional as the size and diversity of their users gets large.Received: 5 June 2003, Revised: 18 November 2003, JEL Classification Numbers: C7, G10, G20, L10, D40, D50. Correspondence to: Eric SmithEric Smith, Martin Shubik: We are grateful to Lloyd Shapley, Duncan Foley, and Doyne Farmer for discussions in the course of this work.     

Economic Valuation of Health for Environmental Policy: Comparing Alternative Approaches. Introduction and Overview

Protecting human health is a primary goal of environmental policy and economic evaluation of health can help policy-makers judge the relative worth of alternative actions. Economists use two distinct approaches in normatively evaluating health. Whereas environmental economists use benefit-cost analysis supported by monetary valuation in terms of willingness-to-pay, health economists evaluate interventions based on cost-effectiveness or cost-utility analysis (CEA), using quality-adjusted life-years (QALY) or similar indexes. This paper provides background on the controversy about the relative merits of these approaches and introduces the remaining papers in the special issue. These papers (with one exception) were presented at a conference sponsored by the Department of Economics at the University of Central Florida with support from the US Environmental Protection Agency. Although CEA might not lead to substantially different implications for environmental policy than benefit-cost analysis, and QALY may provide a benefit transfer tool to fill gaps in the morbidity valuation literature, the papers in this issue raise serious concerns about the suitability of QALY-based CEA for environmental regulatory analysis. QALY does not in general appropriately represent individual preferences for health and CEA is neither independent of income distribution nor adequate to assess efficiency.     

Structure,Clearinghouses and Symmetry

We introduce and justify a taxonomy for the structure of markets and minimal institutions which appear in constructing minimally complex trading structures to perform the functions of price formation, settlement and payments. Each structure is presented as a playable strategic market game and is examined for its efficiency, the number of degrees of freedom and the symmetry properties of the structure     

Discriminatory Price Auctions in Electricity Markets: Low Volatility at the Expense of High Price Levels

A pay-as-offered or discriminatory price auction (DPA) has been proposed to solve the problem of inflated and volatile wholesale electricity prices. Using the experimental method we compare the DPA with a uniform price auction (UPA), strictly controlling for unilateral market power. We find that a DPA indeed substantially reduces price volatility. However, in a no market power design, prices in a DPA converge to the high prices of a uniform price auction with structural market power. That is, the DPA in a no market power environment is as anti-competitive as a UPA with structurally introduced market power.     

Arbitrage opportunities and immunization

It is often argued that an immunization strategy violates arbitrage-free equilibrium. Because immunization is a static concept, we contend that this argument is not valid. This paper examines the immunization strategy in a dynamic setting, and shows that global immunization is feasible for any arbitrage-free affine term structure model, including the parallel shift model. Further, we show that immunization does not violate arbitrage-free pricing because the cost of immunization over time is positive. Consequently, immunization strategies based upon commonly used duration, measures are not theoretically unsound.