Optimal estimation of a finite population mean under generalized random permutation models

Employing certain generalized random permutation models and a general class of linear estimators of a finite population mean, it is shown that many of the conventional estimators are “optimal” in the sense of minimum average mean square error. Simple proofs are provided by using a well-known theorem on UMV estimation. The results also cover certain simple response error situations.     

Comparing migrants to non-migrants: The case of Dutch migration to New Zealand

We analyse post-war Dutch migration to New Zealand. We document that history, reflect on analytical and econometric modelling and then combine a sample of Dutch migrants in New Zealand with a representative sample of Dutch in The Netherlands to estimate wage equations and the determinants of the migration decision. We use the results for ex post evaluation of the migration decision.Joop Hartog is Fellow of IZA (Bonn), CESifo (München), AIAS and Tinbergen Institute (Amsterdam). Work on this project was begun when Hartog was Erskine Visitor at the University of Canterbury, Christchurch New Zealand. Rainer Winkelmann is Fellow of CEPR and IZA (Bonn). This paper is produced as part of a CEPR research programme on European Migration from Economic Analysis to Policy Response, supported by a grant from the Commission of the European Communities under its Human Capital and Mobility Programme (no. ERBCHRXCT940515).It was presented at the European Society for Population Economics meetings in Bonn, June 2000. We gratefully acknowledge comments by Justin Lee Tobias, Jacques Poot, Ed Vytlacil, an anonymous referee and Paul Schultz. Responsible editor: T. Paul Schultz.     

The role of political ties and political uncertainty in corporate innovation

We examine the relationship between firms' political connections and corporate innovation in a European context. We also consider the moderating effect of political connections on the relationship between political uncertainty and firms' innovation. We use two different metrics of innovation: R&D (an input measure), and patent counts (an output measure). We find that firms with former politicians on their board of directors invest less in R&D than their counterpart firms. However, the presence of this type of director on the board is positively associated with the number of a firm's patent applications. It seems that, although political ties reduce the amount of resources devoted to R&D activities, they increase the effectiveness of intellectual rights protection. Results also show that political uncertainty decreases R&D investment but exacerbates the need for legal protection of innovation through patents. According to our results, political connections attenuate the effect of political uncertainty on firm innovation such that the negative (positive) effect of uncertainty on R&D intensity (patents) weakens when the firm is politically connected.     

THE FAILURE TO PREDICT THE GREAT RECESSION—A VIEW THROUGH THE ROLE OF CREDIT

Much has been written about why economists failed to predict the latest crisis. Reading the literature, it seems that this crisis was so obvious that economists must have been blind not to see it coming. We approach this failure by looking at one of the key variables in this analysis, the evolution of credit. We compare the conclusions reached in the recent literature with those that could have been drawn from an ex‐ante analysis. We show that the effect of credit on the business cycle cannot be exploited from a policymaker's point of view.     

THE DEMAND FOR LIQUID ASSETS,CORPORATE SAVING,AND INTERNATIONAL CAPITAL FLOWS

The recent period of capital outflows from emerging economies has coincided with an increase in their corporate saving. In this paper, we model corporate saving as a demand for liquid assets by credit‐constrained firms in a dynamic open‐economy macroeconomic model. We find that the implications of this model are very different from standard models, because the demand for foreign bonds is a complement to domestic investment rather than a substitute. We show that this complementarity is at work when an emerging economy is on its convergence path or when it has a higher TFP growth rate. This framework is consistent with a number of stylized facts found in high‐growth, high‐investment emerging economies.     

FINANCIAL CONSTRAINTS AND INNOVATION: WHY POOR COUNTRIES DON'T CATCH UP

This paper examines micro‐level channels through which financial development can affect such macroeconomic outcomes as level of income. Specifically, we investigate theoretically and empirically how financial constraints affect a firm's innovation activities. Theoretical predictions are tested using unique firm survey data, which provide direct measures for innovations and firm‐specific financial constraints, as well as information on shocks to firms' internal funds that serve as firm‐level instruments for financial constraints. We find unambiguous evidence that financial constraints restrain the ability of domestically owned firms to innovate and hence to catch up to the technological frontier.     

Immigration,Growth, and Unemployment: Panel VAR Evidence from OECD Countries

This paper examines empirically the interaction between immigration and host country economic conditions. We employ panel vector autoregression (VAR) techniques for a large annual data set on 22 OECD countries over the period 1987–2009. The VAR approach addresses the endogeneity problem by allowing for endogenous interactions between the variables in the system. Our results provide evidence of migration contribution to host economic prosperity (positive impact on GDP per capita and negative impact on aggregate unemployment, native‐ and foreign‐born unemployment rates). We also find that migration is influenced by host economic conditions (migration responds positively to host GDP per capita and negatively to host total unemployment rate).     

3G“杀手级”业务的产生和培育

3G时代的到来无疑为电信市场的发展带来了机遇和挑战，到底怎样的电信业务能在新时代中脱颖而出，成为业内人士心驰神往的“杀手级”业务，的确是个耐人寻味的问题。在对“杀手级”业务所应具备的基本条件作探讨的同时，对“杀手级”业务的培育策略进行了分析，认为“杀手级”业务本不存在，它的形成是市场多方因素共同努力的结果。     

Occupancy numbers for dynamic heterogeneous populations: Estimate of particles lifetimes

A dynamic model of a heterogeneous population is studied. Particles belonging to a population are divided, at every time t, into a finite number of classes according to their types and the partition changes over time. The role of the occupancy numbers, namely the cardinality of each class, is highlighted. The relationship between the stochastic process of occupancy numbers and the process of particle types is analyzed. The main goal of this paper is the estimation of the lifetime of each particle at a given time t, when the observed data are the history of the process of the number of dead particles up to t. Furthermore, a discrete time approximation of the filter is given.     

Comparing relative importance of the same component in a series system in two environments

The relative performance of a component of a series system in two different environments is considered. The conditional probability of the failure of the system due to the failure of the specified component given that the system failed before time t is regarded as a measure of relative importance of the component to the system. A U-statistic test for checking the equality of the relative importance of the component to the system in two different environments against the alternative that the relative importance is smaller in one of the environments, is proposed. Some simulation results for estimating the power of the test are reported. The proposed test is applied to one real data set and it is seen that a different aspect of the data is brought out by this comparison than that by the comparisons of the absolute importance functions such as the subsurvival functions, considered in earlier studies.