Quadratic estimation in mixed linear models with two variance components

Explicit expressions for Bayes invariant quadratic estimates, biased and unbiased, are presented and proved to cover the entire class of admissible estimates in the considered classes. An unbalanced genetic model is studied for demonstration.     

Asymptotic properties of a generalized regression-type predictor of a finite population variance in probability sampling

A system of predictors for estimating a finite population variance is defined and shown to be asymptotically design-unbiased (ADU) and asymptotically design-consistent (ADC) under probability sampling. An asymptotic mean squared error (MSE) of a generalized regression-type predictor, generated from the system, is obtained. The suggested predictor attains the minimum expected variance of any design-unbiased estimator when the superpopulation model is correct. The generalized regression-type predictor and the predictor suggested by Mukhopadhyay (1990) are compared.     

Have the relative employment prospects for the low-skilled deteriorated after all?

Has the relative unemployment propensity for the low-skilled increased during the 1990s? We address this question empirically, based on two notions of low skills; i) low education, and ii) low ability, conditioned on education and work experience. Ability is identified by previous earnings. Evaluated by the education-based measure, we find that unemployment propensity has not developed unfavourably for the low-skilled. Evaluated by the ability-based measure, it has. We uncover a steady deterioration of employment prospects for persons with low ability relative to others with similar formal qualifications. The adverse employment effects of being low-skilled are stronger the higher is formal education.All correspondence to Knut Røed. The paper is part of the project Sorting, exposed groups and labour market programs financed by the Research Council of Norway. We wish to thank Rolf Aaberge, Paul Gertler, Harald Goldstein, Karl Ove Moene, Jon Strand, Steinar Strøm, Asbjrn Rødseth and an anonymous referee for helpful comments. Responsible editor: John F. Ermisch.     

Evaluating the impact of utility company billing plans on residential energy consumption

Many utility companies offer their customers the choice of participation in an average payment plan, which enables them to pay a fixed sum for their utility bill each month (with final settlement at the end of the billing year), instead of the conventional “pay as you go” billing procedure. Because customers on average payment plans are protected from paying large bills during peak energy-use seasons and because the information about monthly energy use and its cost is perhaps less salient to them, it was hypothesized that customers on the average payment plan would use more electricity than customers not on the plan. Using a nonequivalent control group design, the electricity consumption of a selection of customers of two utility companies (Ns = 475 and 74) was examined. The results showed that there was no evidence to support the hypothesis. Since the logic of hypothesis testing does not permit the ready acceptance of the null hypothesis, several procedural, methodological, and statistical points were made to buttress the conclusion that the average payment plans had no effect on electricity consumption.     

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.     

哲学分析的典范--奥斯汀驳感觉材料理论

奥斯汀对感觉材料理论的驳斥是他运用语言探究方法检查传统哲学论证的一个典型范例.他认为“我们是感知物质事物还是感知感觉材料?”这个传统知觉问题本身似是而非,而建基在“依据错觉的论证”之上的感觉材料理论则包含大量迷惑人的谬误和各种隐藏着的动机.艾耶尔所表述的论证包含许多语词上的误用或滥用以及诸多对知觉事实的错误概括,其真实动机就是要把现实世界观念化或虚幻化.奥斯汀对感觉材料理论的驳斥并非仅具有否定意义,在批驳感觉材料理论过程中,他还在知觉对象、知觉方式、知觉描述、经验性质等方面提出正面的观点.他的观点至少校正了我们思考知觉问题的框架和方向.     

Chance in Guttman scaling

In their recent paper (1977, Social Science Research, 6, 188–196), Kenny and Rubin offer an interpretation of “chance” in Guttman scaling. Their approach is based on the matrix of probabilities p_ij, giving the chance that the ith respondent passes the jth item. It is shown that their interpretation of chance in fact corresponds to a stochastic model of a perfect unidimensional scale. An alternative condition for chance based on the matrix of p_ij's is proposed. This is then proved to be equivalent to the usual interpretation.     

论“J·阿尔弗瑞德·普鲁弗洛克的情歌”的语言艺术

"J.阿尔弗瑞德.普鲁弗洛克的情歌"是T.S.艾略特语言艺术精湛的典型范例。艾略特在诗歌中大用意象,巧用意象,并运用了丰富的文学和文化暗指;同时,借助拼贴、反复和组合前人作品中看似无关的片段等语言手段来突现诗歌中奥妙鲜明的意象,给诗歌的表达带来沉郁顿挫、一咏三叹的韵味,使灰暗、无奈的主调显露得淋漓尽致,充分展示了诗作丰富的内涵和外延,从而开创了一种新的诗歌表达方式。     

Welfare generosity, pregnancies and abortions among unmarried AFDC recipients

Even before the 1996 overhaul of the U.S. welfare system, a number of states had ended the practice of paying extra benefits to families who have additional children while receiving welfare. Proponents believe that this reform can reduce births to recipients, however many worry that it may encourage women to obtain abortions. Using a sample of unmarried AFDC recipients from the NLSY, we estimate a bivariate probit model of pregnancy and, conditional on becoming pregnant, the probability of abortion. Our results lend some support for the proposition that reducing incremental AFDC benefits will decrease pregnancies without increasing abortions. Received: 16 April 1998/Accepted: 11 March 1999