The sale of small firms: a multidimensional analysis

Summary. This paper endogeneizes the security voting structure in an auction mechanism used to sell a small firm. The design of security voting structure allows the seller to choose between two objectives which are not mutually consistent. If the seller wants to maximize his revenue, he should retain some shares to benefit from the future dividends generated by the acquirer. At the opposite, if he wants to sell his firm to the most efficient candidate, he should sell all the shares. Received: July 4, 2001; revised version: October 31, 2002 RID="*" ID="*" The paper has benefited from a number of comments from the anonymous referees. Correspondence to: C. At     

A simple axiomatization and constructive representation proof for choquet expected utility

>P>Summary. We provide a set of simple and intuitive set of axioms that allow for a direct and constructive proof of the Choquet Expected Utility representation for decision making under uncertainty. Received: October 29, 2002; revised version: November 13, 2002 RID="*" ID="*" We thank Matthew Ryan for very useful comments and suggestions on related work and for encouraging us to write this note. Correspondence to: S. Grant     

Existence of a competitive equilibrium in a one sector growth model with heterogeneous agents and irreversible investment

Summary. We prove existence of a competitive equilibrium in a version of a Ramsey (one sector) model in which agents are heterogeneous and gross investment is constrained to be non negative. We do so by converting the infinite-dimensional fixed point problem stated in terms of prices and commodities into a finite-dimensional Negishi problem involving individual weights in a social value function. This method allows us to obtain detailed results concerning the properties of competitive equilibria. Because of the simplicity of the techniques utilized our approach is amenable to be adapted by practitioners in analogous problems often studied in macroeconomics. Received: September 13, 2001; revised version: December 9, 2002 RID="*" ID="*" We are grateful to Tapan Mitra for pointing out errors as well as making very valuable suggestions. Thanks are due to Raouf Boucekkine and Jorge Duran for additional helpful discussions. We also thank an anonymous referee for his/her helpful comments. The second author acknowledges the financial support of the Belgian Ministry of Scientific Research (Grant ARC 99/04-235 “Growth and incentive design”) and of the Belgian Federal Goverment (Grant PAI P5/10, “Equilibrium theory and optimization for public policy and industry regulation”). Correspondence to: C. Le Van     

A two-sector overlapping generations model with heterogeneous capital

Summary. This paper characterizes the existence and stability properties of steady state solutions as well as the nature of transition paths of a two-sector growth model with heterogeneous capital. It compares the properties of a Cobb-Douglas–Leontief economy with heterogeneous capital with the properties of the same economy with homogeneous capital. The model with heterogeneous capital reveals a set of characteristics different to those of the model with homogeneous capital. These include the saddle-path stability of the non-trivial steady state as well as the possibility of overshooting and in contrast to the homogeneous capital case, the possibility of damped oscillations along the transition path for realistic parameter values. Received: September 21, 2001; revised version: November 21, 2002 RID="*" ID="*" We thank Costas Azariadis, and Laurie Conway for helpful comments on a previous draft. The paper has substantially benefited from the feedback of an anonymous referee. Correspondence to: R. Wendner     

Endogenous fluctuations in the demand for education

Abstract. Enrollment rates to higher education reveal a quite large variation over time which cannot be explained by productivity shocks alone. We develop a human capital investment model in an overlapping generations framework that features endogenous fluctuations in the demand for education. Agents are heterogeneous in their beliefs about future wage differentials. An evolutionary competition between the heterogeneous beliefs determines the fraction of the newborn generation having a certain belief. Costly access to information on the returns to education induces agents to use potentially destabilizing backward looking prediction rules. Only if previous generations experience regret about their human capital investment decisions, will agents choose a more sophisticated prediction rule that dampens the cycle. Access to information becomes key for stable flows to higher education. RID="*" ID="*"We would like to thank Cars Hommes, Florian Wagener, seminar participants at the University of Amsterdam, participants of the workshop on ‘Skill Needs and Labor Market Dynamics’ at the Wissenschaftszentrum Berlin für Sozialforschung (WZB) for helpful discussions, and an editor of this Journal and three anonymous referees for their comments. Tuinstra's research is supported by the Netherlands Organisation for Scientific Research (NWO) under a MaG-Pionier grant. Neugart acknowledges financial support from the German Ministry of Education. Parts of the research were done while Tuinstra was visiting the WZB and when Neugart was visiting CeNDEF. Correspondence to: The research for this paper was done while the first author was affiliated with the Wissenschaftszentrum Berlin für Sozialforschung.     

On bubbling dynamics generated by a stochastic model of herd behavior

This paper suggests a class of stochastic collective learning processes exhibiting very irregular behavior. In particular, there are multimodal long run distributions. Some of these modes may vanish as the population size increases. This may be thought of as “bubbles” persistent for a finite range of population sizes but disappearing in the limit. The limit distribution proves to be a discontinuous function of parameters determining the learning process. This gives rise to another type of “bubbles”: limit outcomes corresponding to small perturbations of parameters are different. Since an agent's decision rule involves imitation of the majority choice in a random sample of other members of the population, the resulting collective dynamics exhibit “herding” or “epidemic” features. RID="*" ID="*" We are grateful to two anonymous referees for the comments and suggestions. Correspondence to: L. Gaio     

The option of joint purchase in vertically differentiated markets

Summary. Within the framework proposed by Mussa and Rosen (1978) for modelling quality differentiation, consumers are assumed to make mutually exclusive purchases. A unique pure strategy equilibrium exists in this case. In this note, we allow consumers to buy simultaneously different variants of the differentiated good. We call this the “joint purchase option”. The paper proposes a detailed analysis of price competition when this option is opened: first, we show that either uniqueness, or multiplicity, or absence of price equilibrium arise, depending on the utility derived from joint purchase relative to exclusive purchase. Second, we characterize these equilibria, whenever they exist. Received: July 25, 2001; revised version: October 21, 2002 RID="*" ID="*" The second author gratefully acknowledges the financial support from Interuniversity Attraction Pole Program- Belgian State- Federal Office for Scientific, Technical and Cultural Affairs under contract PAI 5/26. Correspondence to: X.Y. Wauthy     

Cournot-Nash and Lindahl equilibria in pure public “bad” economies

Summary. Using a general equilibrium framework, this paper analyzes the equilibrium provision of a pure public bad commodity (for example pollution). Considering a finite economy with one desired private good and one pure public “bad” we explicitly introduce the concept of Lindahl equilibrium and the Lindahl prices into a pure public bad economy. Then, the Lindahl provision is analyzed and compared with the Cournot-Nash provision. The main results for economies with heterogeneous agents state that the asymptotic Lindahl allocation of the pure public bad is the null allocation. In contrast, the asymptotic Cournot-Nash provision of the public bad might approach infinity. Other results were obtained in concert with the broad analysis of the large finite economies with pure public bad commodities. Received: July 26, 2001; revised version: March 12, 2002 RID="*" ID="*" We are indebt to Nicholas Yannelis and anonymous referee for their valuable comments and suggestions. Correspondence to: B. Shitovitz     

Persistent unemployment and co-ordination issues: an evolutionary perspective

Abstract. In this paper we look at unemployment as a phenomenon which reflects the co-ordination problems that characterize out-of-equilibrium processes of adjustment. The analysis carried out shifts the focus from structural factors to the economic process. It shows that unemployment cannot be satisfactorily explained – and policy interventions devised – by focusing only on specific characters of the technology or confining the analysis to structural factors concerning the labour market. The co-ordination mechanisms of adjustment processes rather than the fundamentals of the economy appear, in this light, as the main determinants of differences in unemployment trends in different economies; and monetary policy comes back to the center of the stage as an essential element of the working of these mechanisms. RID="*" ID="*" We thank anonymous referees for their very useful comments, and Elena Lega for the helpful support to the simulation analysis carried out. Correspondence to: J.-L. Gaffard     

Nash and Walras equilibrium via Brouwer

Summary. The existence of Nash and Walras equilibrium is proved via Brouwer's Fixed Point Theorem, without recourse to Kakutani's Fixed Point Theorem for correspondences. The domain of the Walras fixed point map is confined to the price simplex, even when there is production and weakly quasi-convex preferences. The key idea is to replace optimization with “satisficing improvement,” i.e., to replace the Maximum Principle with the “Satisficing Principle.” Received: July 9, 2001; revised version: February 25, 2002 RID="*" ID="*" I wish to thank Ken Arrow, Don Brown, and Andreu Mas-Colell for helpful comments. I first thought about using Brouwer's theorem without Kakutani's extension when I heard Herb Scarf's lectures on mathematical economics as an undergraduate in 1974, and then again when I read Tim Kehoe's 1980 Ph.D dissertation under Herb Scarf, but I did not resolve my confusion until I had to discuss Kehoe's presentation at the celebration for Herb Scarf's 65th birthday in September, 1995. RID="*" ID="*"Correspondence to: C. D. Aliprantis     

Existence and optimality of oligopoly equilibria in linear exchange economies

Summary. We consider a linear exchange economy and its successive replicas. We study the notion of Cournot-Walras equilibrium in which the consumers use the quantities of commodities put on the market as strategic variables. We prove that, generically, if the number of replications is large enough but finite, the competitive behaviour is an oligopoly equilibrium. Then, under a mild condition, which may be interpreted in terms of market regulation and/or market activity, we show that any sequence of oligopoly equilibria of successive replica economies converges to the Walrasian outcome and furthermore that every oligopoly equilibrium of large, but finite, replica is Pareto optimal. Consequently, under the same assumptions on the fundamentals of the economy, one has an asymptotic result on the convergence of oligopoly equilibria to the Walras equilibrium together with a generic existence result for the Cournot-Walras. Received: June 20, 2002; revised version: November 20, 2002 RID="*" ID="*" Part of this paper was written while the second author was visiting the Universidad de Vigo. The support of the department of mathematics is gratefully acknowledged. Correspondence to: J.M. Bonnisseau     

Exact arbitrage and portfolio analysis in large asset markets

Summary. We provide a detailed portfolio analysis for a financial market with an atomless continuum of assets. In the context of an exact arbitrage pricing theory (EAPT), we go beyond the characterization of the existence of important portfolios (normalized riskless, mean, cost, factor and mean-variance efficient portfolios) to furnish exact portfolio compositions in terms of explicit portfolio weights. Such an analysis has not been furnished before in the context of the asymptotic arbitrage pricing theory (APT). We also characterize conditions under which a mean-variance efficient portfolio is a benchmark portfolio used in the EAPT to proxy essential risk. We illustrate our results with several examples of specific financial markets. Received: May 30, 2002; revised version: August 15, 2002 RID="*" ID="*"Some of the results reported here constituted part of Cowles Foundation Discussion Paper– No. 1139 circulated under the title “Hyperfinite Asset Pricing Theory”; additional results were obtained when Sun visited the Department of Economics at Johns Hopkins University during March 2002. This paper was presented at the Conference on Economic Design held at NYU on July 6–9, 2002 Correspondence to: M. A. Khan     

A common trends model of UK core inflation

In this paper the long-run trend in RPI inflation (core inflation) for the UK over the 1961–1997 period is estimated within the framework of a multivariate common trends model which extends the bivariate VAR approach of Quah and Vahey (1995). In this context core inflation is directly linked to money and wage growth and interpreted as the long-run forecast of inflation from a small-scale, cointegrated macroeconomic system. First version received: September 1999/Final version received: October 2001 RID="*" ID="*"  We thank two anonymous referees for many helpful comments and suggestions. Work on this paper was partially conducted when C. Morana was at Heriot-Watt University.     

Indeterminacy in a small open economy with endogenous labor supply

Summary. We establish conditions under which indeterminacy can occur in a small open economy business cycle model with endogenous labor supply. Indeterminacy requires small externalities in technologies with social constant returns to scale, independently of the intertemporal elasticities in both consumption and labor. Received: December 12, 2001; revised version: May 17, 2002 RID="*" ID="*"The paper has benefited from discussions with Jess Benhabib and Mark Weder, as well as from the comments of an anonymous referee. Correspondence to: Q. Meng     

A strategy-proofness characterization of majority rule

Summary. A feasible alternative x is a strong Condorcet winner if for every other feasible alternative y there is some majority coalition that prefers x to y. Let (resp., denote the set of all profiles of linear (resp., merely asymmetric) individual preference relations for which a strong Condorcet winner exists. Majority rule is the only non-dictatorial and strategy-proof social choice rule with domain , and majority rule is the only strategy-proof rule with domain . Received: August 29, 2000; revised version: November 13, 2002 RID="*" ID="*"We are grateful to Wulf Gaertner and our two referees for insightful comments on a previous draft. Correspondence to: D. E. Campbell     

Hospital economic impact from hemostatic matrix usage in cardiac surgery

Objective:

Improved health outcomes can result in economic savings for hospitals and payers. While effectiveness of topical hemostatic agents in cardiac surgery has been demonstrated, evaluations of their economic benefit are limited. This study quantifies the cost consequences to hospitals, based on clinical outcomes, from using a flowable hemostatic matrix vs non-flowable topical hemostatic agents in cardiac surgery.

Research design and methods:

Applying clinical outcomes from a prospective randomized clinical trial, a cost consequence framework was utilized to model the economic impact of comparator groups. From that study, clinical outcomes were obtained and analyzed for a flowable hemostatic matrix (FLOSEAL, Baxter Healthcare Corporation) vs non-flowable topical hemostats (SURGICEL Nu-Knit, Ethicon–Johnson &; Johnson; GELFOAM, Pfizer). Costing analyses focused on the following outcomes: complications, blood transfusions, surgical revisions, and operating room (OR) time. Cardiac surgery costs were analyzed and expressed in 2012 US dollars based on available literature searches and US data. Comparator group variability in cost consequences (i.e., cost savings) was calculated based on annualized impact and scenario testing.

Results:

Results suggest that if a flowable hemostatic matrix (rather than a non-flowable hemostat) was utilized exclusively in 600 mixed cardiac surgeries annually, a hospital could improve patient outcomes by a reduction of 33 major complications, 76 minor complications, 54 surgical revisions, 194 transfusions, and 242?h of OR time. These outcomes correspond to a net annualized cost consequence savings of $5.38 million, with complication avoidance as the largest contributor.

Conclusions:

This cost consequence framework and supportive modeling was used to evaluate the hospital economic impact of outcomes resulting from the usage of various hemostatic agents. These analyses support that cost savings can be achieved from routine use of a flowable hemostatic matrix, rather than a non-flowable topical hemostat, in cardiac surgery.     

Speculative trade, asset prices and investment levels

Summary. In this paper I consider a dynamically complete market model without intrinsic uncertainty. Agents' beliefs are different, but correct in the limit. Some agents are more patient than others. I show that infinitely often share prices are low and the economy stagnates. Also, infinitely often share prices are high and the economy grows. The changes from growth to stagnation and from stagnation to growth are not caused by exogenous shocks. They are caused by speculative trade among agents with different propensities to save and invest. Received: January 8, 2001; revised version: April 11, 2002 RID="*" ID="*" I thank an anonymous referee for helpful comments. I gratefully acknowledge financial support from the National Science Foundation.     

Economic consequences of sequencing biologics in rheumatoid arthritis: a systematic review

Abstract

Background and objectives:

Tumor necrosis factor-alpha (anti-TNF) blocking agents are effective for the treatment of rheumatoid arthritis (RA), with mean response rates of 60–70%. Patients with incomplete response to initial anti-TNF treatment often are switched to other biologic treatments with some success. However, little is known about whether or not switching to anti-TNF or other non-TNF biologic treatments is cost-effective. This study sought to review the economic evidence of sequencing various biologic treatments in RA.

Methods:

A systematic review was conducted of published and unpublished literature (January 2000 to October 2012) on the cost-effectiveness of sequencing biologic treatments in RA after failure of an initial biologic treatment. It included modeling and other economic studies that assessed cost-effectiveness of one or more sequences of biologics. Studies were excluded that evaluated non-biologic sequencing.

Results:

This review of the available evidence suggests that there is limited evidentiary support favoring the cost-effectiveness of switching from one anti-TNF agent to another within the anti-TNF category of biologics. This is due, in large part, to the limited clinical evidence base supporting the incremental efficacy of second- and third-line anti-TNF treatments and to variation on how and when to assess non-response to the first-line biologic. When compared to anti-TNF agents, biologic treatments with a different mechanism of action are more cost-effective as second-line agents.

Limitations:

Not all sequences and patterns of switching, either within or outside of therapeutic class, have been evaluated for clinical benefit and cost-effectiveness, limiting the interpretation of these findings.

Conclusions:

Switching from one anti-TNF agent to another after first-line treatment failure may not be a cost-effective treatment strategy. However, when non-TNF biologics are included in the sequence they are likely to be more cost-effective than anti-TNF specific cycling sequences.     

Is assortative matching efficient?

Summary. This paper develops some general conditions under which complementarities between individual agents imply that assortative matching is efficient. Our analysis has four main findings. First, when agents are organized into equal-sized groups, just as in Becker (1973), the presence of within-group complementarities is sufficient for stratification to be efficient. Second, if group sizes vary, assortative matching may not be efficient even though complementarities are present, unless particular functional form assumptions are imposed. Third, the connection between assortative matching, complementarities and efficiency reemerges if one considers sequences of replications of the economy in which individual coalitions are uniformly bounded in size. Fourth, the presence of feedbacks from the composition of group memberships has important effects on efficient allocations and breaks any simple link between assortative matching and efficiency. Together, these results suggest that the characterization of the cross-section evolution of an efficiently sorted economy is likely to be highly complex. Received: September 25, 2001; revised version: February 26, 2002 RID="*" ID="*" We thank William Brock for many helpful conversations and Scott Page for detailed comments on an earlier draft of this paper. The National Science Foundation, John D. and Catherine T. MacArthur Foundation and Center for Urban Land Economic Research have generously provided financial support. Correspondence to: S. N. Durlauf     

Evolutionary foundations of aggregate-taking behavior

Summary. I show that aggregate-taking behavior is often evolutionarily stable for finite population in symmetric games in which payoff depends only on own strategy and an aggregate. I provide economic examples exhibiting this phenomenon. Received: August 27, 2001; revised version: January 29, 2002 RID="*" ID="*" The paper has profited from the comments of Maria Montero, Burkhard Hehenkamp, Wolfgang Leininger, and Dave Furth. Financial support from the DFG via Postgraduate Programme at the University of Dortmund and via SFB 504 at the University of Mannheim is acknowledged. RID="*" ID="*" Present address: University of Mannheim, SFB 504, L 13, 15, 68131 Mannheim, Germany (e-mail: possajen@sfb504.uni-mannheim.de)