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     

Estimation in Two-Stage Models with Heteroscedasticity

A surprising number of important problems can be cast in the framework of estimating a mean and variance using data arising from a two-stage structure. The first stage is a random sampling of "units" with some quantity of interest associated with the unit. The second stage produces an estimate of that quantity and usually, but not always, an estimated standard error, which may change considerably across units. Heteroscedasticity in the estimates over different units can arise for a number of reasons, including variation associated with the unit and changing sampling effort over units. This paper presents a broad discussion of the problem of making inferences for the population mean and variance associated with the unobserved true values at the first stage of sampling. A careful discussion of the causes of heteroscedasticity is given, followed by an examination of ways in which inferences can be carried out in a manner that is robust to the nature of the within unit heteroscedasticity. Among the conclusions are that under any type of heteroscedasticity, an unbiased estimate of the mean and the variance of the estimated mean can be obtained by using the estimates as if they were true unobserved values from the first stage. The issue of using the mean versus a weighted average which tries to account for the heteroscedasticity is also discussed. An unbiased estimate of the population variance is given and the variance of this estimate and its covariance with the estimated mean is provided under various types of heteroscedasticity. The two-stage setting arises in many contexts including the one-way random effects models with replication, meta-analysis, multi-stage sampling from finite populations and random coefficients models. We will motivate and illustrate the problem with data arising from these various contexts with the goal of providing a unified framework for addressing such problems.     

WHAT'S TO KNOW ABOUT THE CREDIBILITY OF EMPIRICAL ECONOMICS?

The scientific credibility of economics is itself a scientific question that can be addressed with both theoretical speculations and empirical data. In this review, we examine the major parameters that are expected to affect the credibility of empirical economics: sample size, magnitude of pursued effects, number and pre‐selection of tested relationships, flexibility and lack of standardization in designs, definitions, outcomes and analyses, financial and other interests and prejudices, and the multiplicity and fragmentation of efforts. We summarize and discuss the empirical evidence on the lack of a robust reproducibility culture in economics and business research, the prevalence of potential publication and other selective reporting biases, and other failures and biases in the market of scientific information. Overall, the credibility of the economics literature is likely to be modest or even low.     

The estimation of union wage differentials and the impact of methodological choices

This paper demonstrates that methodological differences can matter a lot in the estimation of union/non-union wage differentials. Using individual-level data from the 1991 Wave of the British Household Panel Survey and a model evolved from replicating six existing British studies, we find that the model specification adopted has an important impact on the estimated differential and that the choice of which group means to use when evaluating the mean differential in multi-equation models is of considerable importance. There are also important differences between membership and coverage differentials and the earnings measure used and sample selected also make a difference. However, apart from firm size, the contents of the control vector used is not found to be of great importance.     

On Estimators of the Nearest Neighbour Distance Distribution Function for Stationary Point Processes

There are three approaches for the estimation of the distribution function D(r) of distance to the nearest neighbour of a stationary point process: the border method, the Hanisch method and the Kaplan-Meier approach. The corresponding estimators and some modifications are compared with respect to bias and mean squared error (mse). Simulations for Poisson, cluster and hard-core processes show that the classical border estimator has good properties; still better is the Hanisch estimator. Typically, mse depends on r, having small values for small and large r and a maximum in between. The mse is not reduced if the exact intensity λ (if known) or intensity estimators from larger windows are built in the estimators of D(r); in contrast, the intensity estimator should have the same precision as that of λ D(r). In the case of replicated estimation from more than one window the best way of pooling the subwindow estimates is averaging by weights which are proportional to squared point numbers.     

ANOTHER LOOK AT ‘BANK COMPETITION AND FINANCIAL STABILITY: MUCH ADO ABOUT NOTHING’?

This study replicates Zigraiova and Havranek's (2016) meta-analysis of banking competition and financial stability. It performs multiple types of replications: a ‘Reproduction’ replication where Z&H's data and code are verified to reproduce the results of their study; a ‘Repetition’ replication where the studies used by Z&H are independently recoded and then re-analysed; an ‘Extension’ replication where additional studies on banking competition and stability are analysed; and a ‘Robustness Analysis’ where we check Z&H's results using an alternative empirical procedure. Our analysis strongly confirms Z&H's main finding that competition in the banking sector has an economically negligible effect on financial stability. This result is consistently confirmed across a variety of replication analyses. Most impressively, we confirm their finding even when we analyse a completely independent set of 35 studies not included in Z&H's meta-analysis. Our results for Z&H's other findings are less supportive. As the first comprehensive replication of a meta-analysis, this study also provides insights into the robustness of meta-analysis. We find that meta-regression analysis, where estimated effects are related to data, estimation, and study characteristics, is sensitive to how data are coded and to the choice of estimation procedure; and that this sensitivity extends to ‘best practice’ estimates.     

Measuring conditional cooperation: a replication study in Russia

We replicate the strategy-method experiment by Fischbacher et al. (Econ. Lett. 71:397–404, 2001) developed to measure attitudes towards cooperation in a one-shot public goods game. We collected data from 160 students at four different universities across urban and rural Russia. Using the classification proposed by Fischbacher et al. (2001) we find that the distribution of types is very similar across the four locations. The share of conditional cooperators in our Russian subject pools is comparable to the one found by Fischbacher et al. in a Swiss subject pool. However, the distribution of the other types differs from the one found in Switzerland.     

The customer-based corporate reputation scale: Replication and short form

Corporate reputation attracts significant attention among marketing scholars. However, researchers often overlook customers' opinions specifically. Walsh and Beatty [Walsh, G., Beatty, S.E., Measuring Customer-based Corporate Reputation: Scale Development, Validation, and Application. J Acad Mark Sci 2007; 35(1): 127–143.] identify dimensions of customer-based corporate reputation (CBR); they develop scales to measure these dimensions. Researchers in the present study use the Walsh and Beatty CBR scale in the UK and Germany across contexts to study the cross-cultural validity of the measure of customer-based corporate reputation. This study assesses an abbreviated version of the CBR scale (with 15 items). The CBR Short scale has equally good dimensional properties as the original scale. The paper ends with implications for cross-cultural marketing research and management.