An Equilibrium Theory of Learning,Search, and Wages

We examine the labor market effects of incomplete information about the workers' own job‐finding process. Search outcomes convey valuable information, and learning from search generates endogenous heterogeneity in workers' beliefs about their job‐finding probability. We characterize this process and analyze its interactions with job creation and wage determination. Our theory sheds new light on how unemployment can affect workers' labor market outcomes and wage determination, providing a rational explanation for discouragement as the consequence of negative search outcomes. In particular, longer unemployment durations are likely to be followed by lower reemployment wages because a worker's beliefs about his job‐finding process deteriorate with unemployment duration. Moreover, our analysis provides a set of useful results on dynamic programming with optimal learning.     

失业保险给付期限差异下的失业持续时间研究

本文对享受不同失业保险给付期限的失业者的失业持续时间差异进行了实证研究。根据工作搜寻理论,应用存活分析方法建立了含有失业保险给付期限因素的失业持续时间模型,并对青岛市失业者登记数据进行了实证研究。结果表明:享受失业保险者的失业持续时间明显长于不享受失业保险者的失业持续时间,在失业保险给付额度相同的条件下,失业保险给付期限与失业持续时间成同向变动关系。     

Two Questions about European Unemployment

A general equilibrium search model makes layoff costs affect the aggregate unemployment rate in ways that depend on equilibrium proportions of frictional and structural unemployment that in turn depend on the generosity of government unemployment benefits and skill losses among newly displaced workers. The model explains how, before the 1970s, lower flows into unemployment gave Europe lower unemployment rates than the United States and also how, after 1980, higher durations have kept unemployment rates in Europe persistently higher than in the United States. These outcomes arise from the way Europe's higher firing costs and more generous unemployment compensation make its unemployment rate respond to bigger skill losses among newly displaced workers. Those bigger skill losses also explain why U.S. workers have experienced more earnings volatility since 1980 and why, especially among older workers, hazard rates of gaining employment in Europe now fall sharply with increases in the duration of unemployment.     

Inequality and Unemployment in a Global Economy

This paper develops a new framework for examining the determinants of wage distributions that emphasizes within‐industry reallocation, labor market frictions, and differences in workforce composition across firms. More productive firms pay higher wages and exporting increases the wage paid by a firm with a given productivity. The opening of trade enhances wage inequality and can either raise or reduce unemployment. While wage inequality is higher in a trade equilibrium than in autarky, gradual trade liberalization first increases and later decreases inequality.     

Assortative Matching and Search

In Becker's (1973) neoclassical marriage market model, matching is positively assortaive if types are complements: i.e., match output f(x, y) is supermodular in x and y. We reprise this famous result assuming time‐intensive partner search and transferable output. We prove existence of a search equilibrium with a continuum of types, and then characterize matching. After showing that Becker's conditions on match output no longer suffice for assortative matching, we find sufficient conditions valid for any search frictions and type distribution: supermodularity not only of output f, but also of log f_x and log f_xy. Symmetric submodularity conditions imply negatively assortative matching. Examples show these conditions are necessary.     

中韩两国消费者搜寻信息努力的比较研究

本研究在把信息源分为人员信息源和非人员信息源的基础上,建立了消费者搜寻信息努力、搜寻成果与搜寻满意的结构模型,然后根据此模型对中韩两国消费者搜寻信息努力、搜寻成果与搜寻满意进行比较分析,结果发现两国消费者之间在搜寻信息努力上既有共同性又有差异性,最后根据这些研究结果向中韩两国企业提供了为对方国消费者传递信息的策略性建议.     

Simultaneous Search

We introduce and solve a new class of “downward‐recursive” static portfolio choice problems. An individual simultaneously chooses among ranked stochastic options, and each choice is costly. In the motivational application, just one may be exercised from those that succeed. This often emerges in practice, such as when a student applies to many colleges or when a firm simultaneously tries several technologies. We show that such portfolio choice problems quite generally entail maximizing a submodular function of finite sets—which is NP‐hard in general. Still, we show that a greedy algorithm finds the optimal set, finding first the best singleton, then the best single addition to it, and so on. We show that the optimal choices are “less aggressive” than the sequentially optimal ones, but “more aggressive” than the best singletons. Also, the optimal set in general contains gaps. We provide some comparative statics results on the chosen set.     

Unemployment and Business Cycles

We develop and estimate a general equilibrium search and matching model that accounts for key business cycle properties of macroeconomic aggregates, including labor market variables. In sharp contrast to leading New Keynesian models, we do not impose wage inertia. Instead we derive wage inertia from our specification of how firms and workers negotiate wages. Our model outperforms a variant of the standard New Keynesian Calvo sticky wage model. According to our estimated model, there is a critical interaction between the degree of price stickiness, monetary policy, and the duration of an increase in unemployment benefits.     

Adverse Selection in Competitive Search Equilibrium

We study economies with adverse selection, plus the frictions in competitive search theory. With competitive search, principals post terms of trade (contracts), then agents choose where to apply, and they match bilaterally. Search allows us to analyze the effects of private information on both the intensive and extensive margins (the terms and probability of trade). There always exists a separating equilibrium where each type applies to a different contract. The equilibrium is unique in terms of payoffs. It is not generally efficient. We provide an algorithm for constructing equilibrium. Three applications illustrate the usefulness of the approach, and contrast our results with those in standard contract and search theory.     

Unemployment and Employment Protection in a Unionized Economy with Search Frictions

Abstract. In the theoretical literature, the effects of employment protection on unemployment are ambiguous. Higher employment protection reduces job creation as well as job destruction. However, in most models, wages are bargained individually between workers and firms. Using a conventional matching model in which a monopoly union sets wages, I show that employment protection can unambiguously increase unemployment. Interestingly, I find that tightening the restrictions on redundancies and dismissals may even increase the probability of dismissal.     

Discrete Sequential Search with Group Activities*

Equipment failures can have significant implications in terms of cost and customer satisfaction. Reducing the time required to find the cause of a failure can provide large cost savings and help preserve customer goodwill. Single‐item discrete sequential search models can be used to sequence the tasks in diagnostic search to minimize the expected time required to find the cause of the failure. We increase the utility of the single‐item discrete sequential search model by developing a formulation that includes simple precedence relationships as well as sequence dependent relationships defined by group activities. This formulation can be applied to a number of other problems including determining the sequence for multiple quality control tests on an item, scheduling oil well workovers to maximize the expected increase in oil production, and sequencing tasks in a research project where there is a technological risk associated with each task.     

Minimum Wage Effects on Labor Market Outcomes under Search,Matching, and Endogenous Contact Rates

Building upon a continuous‐time model of search with Nash bargaining in a stationary environment, we analyze the effect of changes in minimum wages on labor market outcomes and welfare. Although minimum wage increases may or may not lead to increases in unemployment in our model, they can be welfare‐improving to labor market participants on both the supply and demand sides of the labor market. We discuss identification of the model using Current Population Survey data on accepted wages and unemployment durations, and show that by incorporating a limited amount of information from the demand side of the market it is possible to obtain credible and precise estimates of all primitive parameters. We show that the optimal minimum wage in 1996 depends critically on whether or not contact rates can be considered to be exogenous and we note that the limited variation in minimum wages makes testing this assumption problematic.     

基于消费者需求与信息搜寻过程的新二维营销战略模型及验证

本项研究从消费者需求与消费者信息搜寻两个维度，将产品市场分为易识常用品市场、易识高档品市场、难识常用品市场、难识高档品市场。基于每一类产品的特征，我们提出不同产品市场的营销战略假设，然后在国内选择五个案例，对我们提出的营销战略假设进行了验证。     

The Benefits and Costs of Using Metadata to Improve Enterprise Document Search

The literature shows that there are many problems with enterprise document search. Studies reveal that typical knowledge workers spend between 10% and 20% of their time searching for documents they never find. While many argue that metadata can improve enterprise document search, in reality few organizations use metadata. This represents a missed opportunity. This article describes the results of two experiments that use simulation to evaluate the actual impact of metadata on the costs and benefits of enterprise search. The first study provides quantitative evidence of the increase in recall and precision that stems from the use of metadata‐enhanced document searches. The second study demonstrates that simple metadata structures can be nearly as effective as complex ones, implying that the cost of creating and maintaining metadata is likely to be lower than generally thought. This is the first study to provide explicit quantitative evidence of the gains that can be achieved from the use of metadata, and one of only a handful of studies that examines the cost of creating and maintaining metadata.     

机构投资者信息搜寻、公开信息透明度与私有信息套利

本文利用特有的机构投资者私有信息搜寻数据,研究了机构投资者的信息搜寻、透明度与私有信息套利的关系。本文的研究发现,机构投资者的信息搜寻和信息披露的透明度降低了私有信息套利,而且机构投资者信息搜寻、信息披露透明度在私有信息套利严重的公司对降低私有信息套利的作用更加明显。同时,本文的研究结果也表明,机构投资者信息搜寻与信息披露透明度对私有信息套利存在交互效应,随着信息披露透明度的提高,机构投资者信息搜寻对私有信息套利的边际效应下降。     

Unemployment and Search for Work: Exploratory Analyses of Labour Market Attachment and its Dynamics

This paper deals with measuring unemployment and labour market attachment in Italy, on the basis of Labour Force Survey data. Based on the answers to a set of questions on search for work, a cluster analysis is performed, which yields four groups, clearly characterized as regards their labour market conditions and attachment. Analyses are then carried out on the gross flows between these groups, estimated over a quarterly interval. Results of the dynamic analysis confirm the relevance of the classification established through exploratory techniques. The various groups exhibit a different dynamic behaviour, thus documenting that the exploratory classification has predictive power.     

消费者搜寻信息努力与影响因素的实证研究——以广告媒体为中心

结果表明,在被假设的广告媒体搜寻信息努力与五个影响因素之间的关系中,四个因素即搜寻态度(+)、自我卷入(+)、产品知识(-)、时间压力(-)与广告媒体搜寻信息努力之间有关系。而消费者感知风险与广告媒体搜寻信息努力之间没有关系。     

Unemployment and Search for Work: Exploratory Analyses of Labour Market Attachment using CPS-Type Data

Abstract. This paper deals with measuring unemployment and labour market attachment in Italy, on the basis of CPS-type survey data. It is shown that the size and rate of unemployment are highly sensitive to modest variations in the definition of unemployment. This motivates a different approach. Based on the answers to a set of questions on search for work, a cluster analysis is performed, which yields four well established groups. Comparing them with the official labour force classifications, two “grey areas” appear at the borders between employment, unemployment and inactivity, which are of some interest in interpreting labour market attachment.     

A Note on “Discrete Sequential Search with Group Activities”

This note comments on a paper published by Wagner and Davis [Decision Sciences (2001), 32(4), 557–573]. These authors present an integer‐programming model for the single‐item discrete sequential search problem with group activities. Based on their experiments, they conjecture that the problem can be solved as a linear program. In this note, we provide a counterexample for which the optimal value of the linear program they propose is different from the optimal value of the integer‐programming model, hence contradicting their conjecture for the specific linear program that they specify. To the best of our knowledge, the conjecture settled in this note was still an open question.     

专业化知识搜寻、管理创新与企业绩效：认知评价的调节作用

本研究基于探索/利用双元分析框架,将管理创新划分为利用式管理创新和探索式管理创新两个维度,并将知识搜寻和认知评价的理论观点整合到现有管理创新采纳与实施过程理论模型中,构建了一个研究模型,以考察双元管理创新的采纳过程及其实施对企业绩效的影响。本文以我国华南地区468家制造型企业为问卷调查对象,对上述研究模型进行实证检验,结果表明:(1)科学型知识搜寻主要促进探索式管理创新;市场型知识搜寻对利用式和探索式管理创新均有正向影响;供应链型知识搜寻主要促进利用式管理创新;(2)科学型知识搜寻与探索式管理创新间的关系同时受到风险性认知(负向)、匹配性认知(正向)和复杂性认知(负向)的调节效应影响;市场型知识搜寻与利用式管理创新间的关系仅受到复杂性认知的负向调节效应影响;供应链型知识搜寻与利用式管理创新间的关系同时受到风险性认知(负向)、匹配性认知(正向)和复杂性认知(正向)的调节效应影响,但其与探索式管理创新间的关系仅受到匹配性认知的负向调节效应影响;(3)利用式管理创新与企业绩效呈倒U型关系;探索式管理创新与企业绩效呈正U型关系。研究结论对于厘清管理创新的复杂采纳过程及其实施机理有一定的理论贡献,同时对企业顺利开展管理创新具有一定的实践启示意义。