A new approach to optimal selection of services in health care organizations.

A new reimbursement policy adopted by Medicare in 1983 caused financial difficulties for many hospitals and health care organizations. Several organizations responded to these difficulties by developing systems to carefully measure their costs of providing services. The purpose of such systems was to provide relevant information about the profitability of hospital services. This paper presents a new method of making hospital service selection decisions: it is based on an optimization model that avoids arbitrary cost allocations as a basis for computing the costs of offering a given service. The new method provides more reliable information about which services are profitable or unprofitable, and it provides an accurate measure of the degree to which a service is profitable or unprofitable. The new method also provides useful information about the sensitivity of the optimal decision to changes in costs and revenues. Specialized algorithms for the optimization model lead to very efficient implementation of the method, even for the largest health care organizations.     

Action Research is Similar to Design Science

In management information systems (MIS) action research is long considered as promising but low-level research approach. It has an utmost relevance because action researchers are working with practitioners to solve the important practical problem. Design science outlined some years ago is just winning a wider audience. Action research was traditionally classified into qualitative research methods. But it seems to be the “wrong” home of action research. We shall show that after comparison of the seven aspects: concrete results of the study, knowledge produced, activities, the intent and the nature of a study, the division of labor in a study and generation, use and test of knowledge, the concordance between the characteristics of action research on the one hand and of design science on the other hand is very good. Hence, action research and design science should next be considered as similar research approaches, and this is a turning point in the history of both action research and design science.     

Marginal distributions of sequential and generalized order statistics

Expressions for marginal distribution functions of sequential order statistics and generalized order statistics are presented without any restrictions imposed on the model parameters. The results are related to the relevation transform, to the distribution of the product of Beta distributed random variables, and to Meijers G-functions. Some selected applications in the areas of moments, conditional distributions, recurrence relations, and reliability properties are shown. Key words:Order statistics; Generalized order statistics; Sequential order statistics; Record values; Distribution theory; Meijers G-function; Recurrence relations; Reliability properties.     

Insuring against the shortfall risk associated with real options

We would like to insure against the risk that a geometric Brownian motion, correlated with the price process of a certain traded asset, is in a set E at time T. In this paper it is shown that the best action one can take to insure against this risk is to buy a binary option on the traded asset. We give explicit formulas in the case that E is an infinite interval. The setting of all our investigations is the Black-Scholes model. Mathematics Subject Classification (2000): 91B28, 60J65, 62P05, 91B30, 62F03 Journal of Economic Literature Classification: G31     

Income taxation when markets are incomplete

We investigate the welfare effects of proportional income taxation in a standard general equilibrium model with incomplete markets (GEI). Formally, our analysis is on the allocative effects of state-contingent income tax reforms. Tax reforms are restricted to be anonymous, publicly and truthfully announced before markets open, and they are required to result in an ex-post constrained efficient allocation. Our main result is to show that there do typically exist contingent tax reforms that are Pareto improving. These reforms, acting directly on the asset span, modify private risk-sharing opportunities. Thus, unlike most of the GEI literature, the type of policy transmission mechanism considered does not rely on second-order, relative spot price effects. Yet, the key welfare effects of our tax reforms are substantially equivalent to those induced through changes in relative spot prices, as, for example, in Geanakoplos and Polemarchakis (1986), Geanakoplos et al. (1990), or in Citanna et al. (2001). Mathematics Subject Classification (2000): 58E17, 46N10, 93B29 Journal of Economic Literature Classification: D52, H21, H24, H25     

Representing complete and incomplete subjective linear preferences on random numbers

We show that preferences on random numbers which satisfy certain natural properties can be represented, in the setting of topological vector spaces, by a suitable family of continuous previsions which is, in a sense, unique. Moreover, for most commonly used spaces of random numbers, we establish that one can derive these preferences, via an expectation operator, from a suitable family of probabilities (whether or not finitely additive). Mathematics Subject Classification (2000): 06A06, 62C05, 91B06 Journal of Economic Literature Classification: D11, D81     

Reduced Form Auctions Revisited

This note uses the Theorem of the Alternative to prove new results on the implementability of general, asymmetric auctions, and to provide simpler proofs of known results for symmetric auctions. The tradeoff is that type spaces are taken to be finite.     

Human Capital and Growth Cycles

This paper studies the dynamic interaction between human capital accumulation and economic growth. Capital market imperfections and an indivisibility in human capital investment prevent poor agents from accumulating skills, the acquisition of which positively affects technological progress. More productive technologies in turn require more sophisticated qualification and involve higher training costs. The equilibrium dynamics can be characterized by the joint evolution of productivity growth, the schooling costs, and the income distribution. Under our assumptions, individual incomes follow a non-linear Markov chain. This non-linearity generates endogenous fluctuations of schooling activities and the rate at which productivity improvements occur. We thank an anonymous referee for many helpful suggestions. Support from the German Research Foundation (DFG) under grant KA1519/2-2 is gratefully acknowledged.     

Effective regulation versus tacit collusion in the long-distance market: an empirical analysis

Regulatory decisions often must be made in an atmosphere of uncertainty, and arguments presented by the affected parties frequently add to, rather than resolve, that uncertainty. Here, we examine several of the deregulatory decisions affecting the long-distance market that were rendered by the FCC over the two-decade period following the divestiture of AT&T. Our purpose is to provide empirical evidence relevant to some of the arguments regarding market conditions that were presented during that period. Findings suggest that some of the more prominent allegations are not supported by the data.      

On a clear day you might see an environmental Kuznets curve

We shed some new light on the Environmental Kuznets curve (EKC) and show how it can be viewed as a particular form of equilibrium relationship, where technology and preference parameters determine the shape of the curve. In contrast to most of the literature on the EKC, we estimate a theoretically consistent model on long-run data (Swedish sulfur emission, covering the period 1900–2002). Furthermore, we test and date structural change. The model suggests four regimes, 1900–1918, 1919–1933, 1934–1967 and 1968–2002, generating four rather different patterns for pollution over time. The policy-conclusions are consonant with Pearce’s general view about the EKC: there is no theoretical presumption that it has an inverted U shape, nor should any country try to “grow out of the environmental problems” without analyzing the benefits and costs of so doing.