A Framework for Reconsidering the Lake Wobegon Effect

The Lake Wobegon Effect (LWE) describes the potential measurement-error bias introduced into survey-based analyses of education issues. Although this effect potentially applies to any student-report variable, the systematic overreporting of academic achievements such as grade point average is often of preeminent concern. This concern can be easily circumvented if official records data are available; however, many researchers can only access student-reported data. In this article, the authors examine whether using student-survey data in place of official records data meaningfully biases regression estimates. They motivate their contribution by noting a useful statistical feature of overreporting on bounded variables such as grade point average. Specifically, the misreports will be negatively correlated with the true grade point average, yielding a form of nonclassical measurement error that actually counteracts the bias. The authors connect this observation to reliability ratios used in labor economics, which are simple ways to adjust for attenuation bias, when needed. In two applications, we find that it is unnecessary to correct for the LWE bias because it is so small.     

Return to education in Finland

This study presents estimates of the return to education in Finland using an individual-level data set that also includes ability measures and information on family background. It is found that ability test scores have a strong effect on the choice of education and on subsequent earnings. Estimating the return to education with no information on ability leads to an upward bias in the estimates. However, this bias is more than offset by a downward bias caused by endogeneity or measurement error. Instrumental variables estimates that utilize family background variables as instruments produce estimates of the return to schooling that are approximately 60% higher than the least squares estimates.     

An Empirical Analysis of the Bias and Rationality of Profit Forecasts Published in New Issue Prospectuses

Our study sets out to assess the accuracy of profit forecasts made by IPOs in Hong Kong. We use a variety of measures and tests to examine the accuracy, bias, rationality, and superiority of earnings estimates. The results show that forecast accuracy compares favourably with the findings from the developed economies of Australia, Britain, Canada, and New Zealand. Forecasts are shown to be superior to the predictions from time series models. IPOs tend to underforecast in the sense that actual profits exceed the forecasts. The rationality tests show mixed results. Cross-sectional analyses of forecast accuracy have poor explanatory power although the Big Six reporting accountants are associated with smaller forecast errors.     

Statistics by Gender: Measures to Reduce Gender Bias in Agricultural Surveys

Statistics by gender has been the concern of policy makers in the recent past years. The demand on data disaggregated by gender has led the survey statistician to collect data and tabulate statistics by gender. In this paper, some measures will be suggested to avoid and reduce gender bias for data collection and tabulation in agricultural surveys.     

Internet Job Search and Labor Market Outcome

This study examines the effect of the use of internet job search (IJS) on individual wages. The data utilized in the study are obtained from the Internet and Computer Use Dictionary in the Current Population Survey of September 2001 and October 2003. An Oaxaca Decomposition is used to examine the extent to which wage differences are influenced by IJS. The results show that accessibility to the internet is a crucial factor in the decision of an individual to utilize the internet for job search activities. However, no clear evidence exists that IJS increases individual wages. Additionally, the study also demonstrates that IJS is subject to self-selection bias. Thus, failure to control for self-selection bias results in a very serious bias in estimation.     

扇形排孔多排同段爆破技术在我矿的应用

介绍了扇形排孔侧向自由面多排同段爆破技术在狮子山铜矿大团山矿段25A采场的实践,较成功地解决了由于矿岩破碎,部分硐室垮落严重,无法实施正常爆破次序条件下的爆破技术问题,取得了很好的爆破效果。     

Economies of scale and trade policy: The median voter model revisited

Why do some political economy models perform so poorly in predicting actual trade policy? Do scale economies provide the missing puzzle to our understanding of the anti-trade bias? By integrating economies of scale in production, this paper theoretically reinstates the median voter model as in Mayer [Mayer, W. (1984). Endogenous tariff formation. The American Economic Review, 74, 970–985] as a suitable political economy model in predicting trade policy. The modified model generates the scope for the anti-trade bias and predicts that sometimes economic, rather than political, considerations may lead to restrictive trade.     

Home-field advantage or a matter of ambiguity aversion? Local bias among German individual investors

This paper investigates whether familiarity induced by ambiguity aversion can help explaining the local bias phenomenon among individual investors. Using geographic closeness as a proxy for investor familiarity, we find that investors pull out of (unfamiliar) remote stocks and pour into (familiar) local stocks during times of increased market uncertainty. Moreover, the magnitude of this ‘flight to familiarity’ increases in the spread of an investor's ambiguity (about expected returns) between local and remote stocks. Our results prove robust to a number of alternative explanations of local bias. Specifically, we rule out a ‘home-field advantage’, where investors are able to translate information advantages about nearby companies into excess returns on their local stockholdings. We conclude that individual investors’ local bias is induced by ambiguity aversion in the portfolio selection process rather than a trading strategy based on superior information about local companies.     

线性集成稳压器的安全应用

集成稳压器应用非常广泛，而在使用中却存在安全保护的问题，本文介绍了一些主要的保护方法，并作了简要的分析     

A Middle Class Image of Society

We studied undercoverage and nonresponse in a telephone survey among the population of the City ofGroningen, the Netherlands. The original sample, drawn from the municipal population register,contained 7000 individuals. For 37 percent of them, the telephone company was unable to produce a validtelephone number. Of those with a known telephone number, 49 percent did not answer the telephone orrefused to cooperate. As a result, the final respondents comprised merely 32 percent of the originalsample. To study distributional bias, we used individual-level data compiled from municipal records asour benchmark. Bivariate as well as multivariate analyses showed the undercoverage to be stronglyrelated to all sociodemographic variables studied, except gender. Nonresponse was related to age, countryof origin, marital status, and household size and composition, but not to gender, unemployment, socialassistance benefit, and education. Both undercoverage and nonresponse contributed to a strong middleclass bias in the final data set: middle-aged and older, economically secure people, of Dutch origin andliving with others in a household are overrepresented, while persons in disadvantaged and marginalpositions, such as the young, people of foreign stock, the unemployed, persons depending on publicincome support and singles are underrepresented.