Interim Information in Long-Term Contracts

We study how long-term contracts condition on a natural flow of information that reduces asymmetric information over time. If such interim information is verifiable, optimal contracts achieve the first best. Under nonverifiability, the optimal contract depends on the signal's accuracy and timing. Introducing signal manipulation as a parameterization of verifiability reveals a trade-off between accuracy and manipulability. Signals that are accurate, received early, or hard to manipulate enable the principal to extract all rents and adjust allocations closer to the first best. Imprecise, late, and manipulable signals affect only future allocations and leave rents to efficient types.     

Robust min–max portfolio strategies for rival forecast and risk scenarios

We consider an extension of the Markowitz mean–variance optimization framework to multiple return and risk scenarios. It is well known that asset return forecasts and risk estimates are inherently inaccurate. The method proposed provides a means for considering rival representations of the future. The optimal portfolio is computed, simultaneously with the worst case, to take account of all rival scenarios. This is a min-max strategy which is essentially equivalent to a robust pooling of the scenarios. Robustness is ensured by the noninferiority of min–max. For example, a basic worst-case optimal return is guaranteed in view of multiple return scenarios. If robustness happens to have too high a cost, guided by the min–max pooling, it is also possible to explore other pooling alternatives. A min–max algorithm is used to solve the problem and illustrate the robust character of min–max with return and risk scenarios. We study the properties of the min–max risk–return frontier and compare with the potentially suboptimal worst-case where the investment strategy and the worst case are computed separately.     

Quality and Location Choices under Price Regulation

In a model of spatial competition, we analyze the equilibrium outcomes in markets where the product price is exogenous. Using an extended version of the Hotelling model, we assume that firms choose their locations and the quality of the product they supply. We derive the optimal price set by a welfarist regulator. If the regulator can commit to a price prior to the choice of locations, the optimal (second-best) price causes overinvestment in quality and an insufficient degree of horizontal differentiation (compared with the first-best solution) if the transportation cost of consumers is sufficiently high. Under partial commitment, where the regulator is not able to commit prior to location choices, the optimal price induces first-best quality, but horizontal differentiation is inefficiently high.     

Full pooling in multi-period contracting with adverse selection and noncommitment

This paper analyses multi-period regulation or procurement policies under asymmetric information between the regulator and regulated firms. As well known in the literature, some degree of separation is always optimal under any form of commitment. In contrast, we show that full pooling is optimal under noncommitment when the discount factor is sufficiently high. We also discuss the meaning of full pooling under double randomization. Finally, we provide a graphical analysis of the second-best policy in terms of the regulator's commitment capacity. Received: 4 December 1996 / 7 October 1999     

Reputation,Trust, and Rebates: How Online Auction Markets Can Improve Their Feedback Mechanisms

Reputation systems constitute an important institution, helping sustain trust in online auction markets. However, only half of buyers leave feedback after transactions, and nearly all feedback is positive. In this paper, I propose a mechanism whereby sellers can provide rebates (not necessarily in monetary form) to buyers contingent upon buyers' provision of reports. Using a game theoretical model, I show how the mechanism can increase unbiased reporting. There exists a pooling equilibrium where both good and bad sellers choose the rebate option, even though their true types are revealed through feedback. The mechanism also induces bad sellers to improve the quality of the contract.     

The Alpha Risk of Taguchi Method for LTB Type Quality Characteristic with L<Subscript>8</Subscript>

In Taguchi’s parameter design, the significant parameter levels are found by maximising the signal-to-noise ratio of the quality characteristic. In the analysis of variance (ANOVA) of signal-to-noise ratio, the combination of column effects to better estimate error variance is referred to as pooling. Taguchi has suggested the strategy of pooling up. When using the pooling-up strategy, there will be a tendency to make the alpha mistake more often. In this paper, it is assumed that (1) the quality chartacteristic is normally distributed and (2) the mean and standard deviation of each factor level combination are equal, then the null hypothesis should be no significant factor. Thus, the alpha risk is that some factors are misidentified as significant factors. The purpose of this paper is to investigate the alpha risk of the Taguchi method for the-larger-the-better (LTB) type problem with orthogonal array, L₈, by simulation. The results show that the alpha risk is very high.     

An applied stochastic model of the quality–quantity trade-off in the public health care sector

It is a striking feature of the many of the developing country public service sectors that the sectors in question often overproduce the quantity of services but underproduce the quality. This feature, which is exemplified in this paper, is rooted in a wide spectrum of economic and sociological factors ranging from the economic and sociological profile of the service receiving people to the asymmetric density of service-receiving population across their regions. This feature, we conjecture, is a source of a considerable degree of suboptimality in some of the developing countries. If our conjecture is correct, correcting such suboptimalities is likely to yield significant welfare improvements that could help speed up the process of development in the underdeveloped regions of the world. To analyze the supoopimalites in question, we will first develop a concept (and a model) of optimal quality in the public service sector, which indicates the level of quality that maximizes expected public satisfaction subject to available resources. Resources are used in an efficient manner to produce the service in question. The concept and the model in the paper make a needed contribution to the quality discourse by presenting a way of determining the quality improvements (or adjustments) necessary to achieve optimum in the public service sector. The paper presents an application (a case study) of this new concept in the public healthcare sector in Turkey, and explores the differences between the actual and optimal quality in the sector in question. It turns out that there is a considerable difference between the actual and optimal levels of quality (as well as those of quantity) in the Turkish public healthcare sector in an overpopulated city (Istanbul), indicating a significant overproduction of quantity and underproduction of quality. Thus, to achieve the optimal levels, the sector should increase quality and reduce quantity by a considerable margin. The quantified differences (gaps) between actual and optimal levels point out a considerable room for welfare improvement. Optimum-seeking adjustments closing these gaps could be shown to lead to considerable satisfaction and welfare gains, the measurement of which is worthy of future research.     

MARKET MANIPULATION: A SURVEY

Abstract Despite the significant attention that market manipulation has received in recent years many aspects of it are poorly understood. This article identifies from the theoretical and empirical literature what we do and do not know about market manipulation, and suggests directions for future research. We know that manipulation is possible and that it occurs in a wide variety of markets and circumstances. In contrast, we know little about how often manipulation occurs, its effects and how it responds to regulation. Suggested approaches for future research on these issues include: (1) collecting more comprehensive data sets of manipulation cases; (2) using detection controlled estimation methods to overcome sample selection and partial observability problems and (3) conducting controlled experiments. This article also constructs a novel and broad taxonomy of the different types of market manipulation and discusses approaches to defining manipulation.     

To pool or not to pool: What is a good strategy for parameter estimation and forecasting in panel regressions?

This paper considers estimating the slope parameters and forecasting in potentially heterogeneous panel data regressions with a long time dimension. We propose a novel optimal pooling averaging estimator that makes an explicit trade‐off between efficiency gains from pooling and bias due to heterogeneity. By theoretically and numerically comparing various estimators, we find that a uniformly best estimator does not exist and that our new estimator is superior in nonextreme cases and robust in extreme cases. Our results provide practical guidance for the best estimator and forecast depending on features of data and models. We apply our method to examine the determinants of sovereign credit default swap spreads and forecast future spreads.     

Tender evaluation and supplier selection methods in public procurement

The EU procurement directives stipulate that public contracts be awarded to the lowest bidder or to the bidder with the economically most advantageous tender; the latter requiring that a scoring rule be specified. We provide a simple theoretical framework, based on standard microeconomic theory, for tender evaluation (scoring and weighing) and discuss the pros and cons of methods such as highest quality (beauty contest), lowest price and price-and-quality-based evaluations. We argue that the most common method, price-to-quality scoring, is inappropriate for several reasons. It is non-transparent, making accurate representation of the procurer's preferences difficult. It is often open to strategic manipulation, due to dependence on irrelevant alternatives, and it tends to impose particular and unjustified non-linearity in bid prices. The alternative quality-to-price scoring method, where money values are assigned to different quality levels, is a better alternative. However, when the cost of quality is relatively well-known and several providers can offer optimal quality, lowest price is the preferable supplier selection method, while beauty contests may be preferred when purchasing budgets are inflexible.     

Competition in Regulated Markets with Sluggish Beliefs about Quality

We investigate the effect of competition on quality in regulated markets (e.g., health care, higher education, public utilities), using a Hotelling framework, in the presence of sluggish beliefs about quality. We take a differential‐game approach, and derive the open‐loop solution (providers choose the optimal quality investment plan based on demand at the initial period) and the feedback closed‐loop solution (providers observe demand in each period and choose quality in response to current demand). If variable costs are strictly convex, and the degree of cost complementarity between quality and output is not too strong, the steady‐state quality is higher under the open‐loop solution than under the feedback solution. In both solutions, quality and demand move in opposite directions over time on the equilibrium path to the steady‐state. While lower transportation costs or less sluggish beliefs lead to higher quality in both solutions, the quality response is weaker when players use feedback strategies.     

Partnership markets with adverse selection

Ownership positions in large corporations can be traded on anonymous markets, but professional partnerships and worker cooperatives prohibit members from transferring their positions to outsiders without the consent of other insiders. These contrasting policies can be explained by adverse selection, which implies that the joint payoff of the partners is at least as large when continuing rather than departing members choose the terms on which new partners can join. In a separating equilibrium, or a pooling equilibrium in which only low-quality workers apply for positions, market sorting reduces total surplus. The market can sometimes improve on random assignment of workers to firms when there is a pooling equilibrium in which both high- and low-quality types apply.     

Entry Deterrence, Product Quality: Price and Advertising as Signals

I analyze the marketing strategy of an incumbent monopolist facing a threat of entry. Product quality is unknown to consumers, and the monopolist's cost is unknown to the potential entrant. The incumbent uses both price and advertising to signal cost and quality. The monopolist faces a dilemma because signaling a high quality attracts customers but requires a high price, whereas signaling low cost prevents entry but requires a low price. I characterize the unique (stable) separating equilibrium and show that dissipative advertising may be used, while it is never used if either quality or cost is known. Some equilibria may involve pooling on cost. A welfare analysis indicates that potential entry may improve welfare and that the effect of unknown quality is not always negative when it interferes with entry deterrence.     

Possibly-Final Offers

A price-setting seller faces a buyer with unknown reservation value. We show that if the buyer is sufficiently risk averse, the seller can benefit from employing a Possibly-Final Offer (PFO) strategy. In a PFO, if the buyer rejects the seller's initial offer the seller sometimes terminates the interaction. If the seller does not terminate, he follows up with a subsequent, more attractive offer. As the buyer's risk aversion increases, the seller's expected profit under the optimal PFO approaches the full-information profit. These results extend to contexts with endogenous commitment, multiple types of buyers, multidimensional objects, and nonseparable utility functions.     

Incorporating morale into a classical agency model: implications for incentives, effort, and organization

This paper incorporates morale into a standard principal-agent model. When morale is observable, the worker’s effort level, the optimal piece rate, and the firm’s expected profits are all generally increasing in the worker’s level of morale. Furthermore, under reasonable conditions, higher-morale individuals are more responsive to incentives. Finally, when considering morale interdependence, conditions are derived which determine optimal organization strategies in terms of pooling or separating workers, and corresponding staffing policies are discussed.      

Forecasting with nonstationary dynamic factor models

In this paper we analyze the structure and the forecasting performance of the dynamic factor model. It is shown that the forecasts obtained by the factor model imply shrinkage pooling terms, similar to the ones obtained from hierarchical Bayesian models that have been applied successfully in the econometric literature. Thus, the results obtained in this paper provide an additional justification for these and other types of pooling procedures. The expected decrease in MSE for using a factor model versus univariate ARIMA and shrinkage models are studied for the one factor model. Monte Carlo simulations are presented to illustrate this result. A factor model is also built to forecast GNP of European countries and it is shown that the factor model can provide a substantial improvement in forecasts with respect to both univariate and shrinkage univariate forecasts.     

浅论加强建筑工程施工的质量控制的有效途径

建筑工程项目管理的中心问题是施工质量控制。近年来随着我国经济的迅猛发展,建设规模不断扩大,每年投资建设的各类工程项目多达十几亿平方米。施工企业若想在建筑市场站稳脚步,必须采取一系列措施提高建筑工程施工质量,并对施工质量进行有效控制。     

Run length analysis of Shewhart charts applied to drifting processes under an integrative SPC/EPC model

Engineering Process Controllers (EPC) are frequently based on parametrized models. If process conditions change, the parameter estimates used by the controllers may become biased, and the quality characteristics will be affected. To detect such changes it is adequate to use Statistical Process Control (SPC) methods. The run length statistic is commonly used to describe the performance of an SPC chart. This paper develops approximations for the first two moments of the run length distribution of a one-sided Shewhart chart used to detect two types of process changes in a system that is regulated by a given EPC scheme: i) changes in the level parameter; ii) changes in the drift parameter. If the drift parameter shifts, it is further assumed that the form of the drift process changes from a linear trend under white noise (the in-control drift model) into a random walk with drift model. Two different approximations for the run length moments are presented and their accuracy is numerically analyzed. Received: August 1998     

Strategic behavior in a service industry

A model of service duopoly is formulated, where the arrival of customers and their service time in the firm are stochastic. The firms first choose the service capacity, and given the capacity they then choose the price in a Bertrand competition. Capacity choices have a negative externality on the competitor, since increased capacity in one firm decreases its expected full price (price plus cost of waiting) and leads to a flow of customers from the other firm. If the firms choose capacities strategically, it is optimal to underinvest compared to the non‐strategic case, but this result may arise in different ways. By underinvesting the firms commit themselves to longer queues (lower quality) to relax price competition. Copyright © 2002 John Wiley & Sons, Ltd.     

浅析上市公司利润操纵行为及防范

会计信息失真是多方面原因造成的,操纵利润是其主要目的。本文具体分析了上市公司利润操纵的主要方法,并针对性提出了一系列的防范措施,以便近一步消除或抑制利润操纵行为,提高会计信息质量,促进市场经济朝着健康有序的方向发展。