The effects of income imputation on microanalyses: evidence from the European Community Household Panel

Summary.  Social surveys are usually affected by item and unit non-response. Since it is unlikely that a sample of respondents is a random sample, social scientists should take the missing data problem into account in their empirical analyses. Typically, survey methodologists try to simplify the work of data users by 'completing' the data, filling the missing variables through imputation. The aim of the paper is to give data users some guidelines on how to assess the effects of imputation on their microlevel analyses. We focus attention on the potential bias that is caused by imputation in the analysis of income variables, using the European Community Household Panel as an illustration.     

Bayesian Estimation of a Multidimensional Additive Graded Response Model for Correlated Traits

The aim of the article is to propose a Bayesian estimation through Markov chain Monte Carlo of a multidimensional item response theory model for graded responses with an additive structure with correlated latent traits. A simulation study is conducted to evaluate the model parameter recovery under different conditions (sample size, test and subtest length, number of response categories, and correlation structure). The results show that the parameters are well reproduced when the sample size is sufficiently large (n = 1, 000), while the worst recovery is observed for small sample size (n = 500), and four response categories with a short number of test items.     

中美纺织品贸易法律问题解析

在中国入世时承诺的纺织品特殊保障措施（242条款）刚刚终结之际,以历史分析的方法阐述中美纺织品贸易法律制度的产生及演化,并对美国制约中国纺织品进口的法律措施进行全面、细致的分析研究。在此基础上,针对未来最有可能引发中美纺织品贸易摩擦的特定产品过渡性保障机制、美国421条款以及美国有关纺织品的技术性贸易壁垒等法律问题提出策略建议,以期为我国输美纺织品出口企业从容应对贸易摩擦提供有益参考。     

混合题型的IRT等值问题研究

我们称既有0—1评分题,又有多级评分题的试卷为混合题型试卷,简称为混合题型．以往国内对混合题型的测验等值采用的方法是将Logistic模型看成是等级反应模型或拓广的分部评分模型的特例,这种处理方式就可能忽略了项目的猜测因素．为了解决这一问题,本文将三参数的Logistic模型和GRM进行扩展得到混合模型,并针对此模型开发了相应的等值程序．另外,为了检验某次测验0—1评分项目存在猜测,而人为将其忽略所带来的误差大小,本文进行了大量的MonteCarlo模拟实验．实验结果表明,若某测验中0—1评分项目存在猜测而等值时忽略这一事实误用GRM,在绝大部分情况下都比用混合模型等值的误差大而且有显著性差异,并且等值的误差会随着猜测度的的增大而增大．     

Comparing methods for estimating the abilities for the multidimensional models of mixed item types

The maximum likelihood (MLE), the weighted maximum likelihood (WMLE), and the maximum a posteriori (MAP or BMLE) have been widely used to estimate ability parameters in item response theory (IRT), and their precisions and biases have been studied and compared. Multidimensional IRT (MIRT) has been shown to provide better subscore estimates in both paper-and-pencil and computer adaptive tests; thus, it is very important to have an accurate score estimate for the MIRT model. The purpose of this article is to compare the performances of the three estimation methods in the MIRT framework for tests of mixed item types that have both dichotomous and polytomously scored items, and for tests of mixed structured items (simple structured and complex structured). It is found that all three methods perform well for all conditions. For all models studied (one-, two-, three-, and four- dimensional model), WMLE has smaller BIAS and higher reliabilities, but larger RMSE and SE. WMLE and MLE are closer to each other than to BMLE. However, for higher dimensions, BMLE is recommended, especially when there are correlations between the dimensions.     

On some new randomized item sum techniques

A recent quantified version of item count technique (ICT), called the item sum technique (IST), was developed by Trappmann et al. (2014 Trappmann, M., I. Krumpal, A. Kirchner, and B. Jann. 2014. Item sum—A new technique for asking quantitative sensitive questions. Journal of Survey Statistics and Methodology 2 (1):58–77. doi:10.1093/jssam/smt019.[Crossref] , [Google Scholar]). In this method, two subsamples are required to obtain reliable data on the sensitive issues. In this article, we propose three alternative item sum techniques by utilizing an additional randomization device. The main advantage associated with the current study is that in order to estimate population sensitive parameters, it requires only one sample to obtain reliable data on quantitative sensitive issue without jeopardizing the privacy of participants. Furthermore, it reduces the cost, effort, and time as compared to usual IST. It is also free from the requirement of finding optimum subsample sizes as in the usual IST. The mean and variance of these proposed estimators are also derived and compared with those of the usual IST. Through algebraic and nnumerical comparsions, it is observed that the proposed techniques perform better than the usual IST. Moreover, the proposed randomized IST 3 is observed to be unconditionally more effeicient than the proposed IST 1 and IST 2.     

Logistic regression analyses for indirect data

The article’s topic is logistic regression for direct data on the covariates, but indirect data on the endogenous variable. The indirect data may result from a privacy-protecting survey procedure for sensitive characteristics or from statistical disclosure control. Various procedures to generate the indirect data exist. However, we show that it is possible to develop a general approach for logistic regression analyses with indirect data that covers many procedures. We first derive a general algorithm for the maximum likelihood estimation and a general procedure for variance estimation. Subsequently, lots of examples demonstrate the broad applicability of our general framework.     

美国国内贸易法的“421”条款与“双反”措施比较

最近,美国运用<1974年贸易法>"421条款"对我国产品采取特保措施,我国商务部以反倾销、反补贴措施应对.由于<中国入世议定书>第16条"特定产品过渡性保障机制"主要内容与美国<1974年贸易法>"421条款"有较多相同之处,如果其他WTO成员国引用"入世议定书"对我国产品采取特保措施,必然会使我国本来遭受国外反倾销、反补贴(简称"双反")措施重创出口的形势再雪上加霜. 研究"412条款"的由来、特点以及"双反"相关内容,探索建立"双反"快速反应机制,从根本上构建相关法律体系,避免对国内企业造成不必要的经济损失.     

Item nonresponse on income questions in panel surveys: Incidence, imputation and the impact on inequality and mobility

Summary: This paper deals with item nonresponse on income questions in panel surveys and with longitudinal and cross–sectional imputation strategies to cope with this phenomenon. Using data from the German SOEP, we compare income inequality and mobility indicators based only on truly observed information to those derived from observed and imputed observations. First, we find a positive correlation between inequality and imputation. Secondly, income mobility appears to be significantly understated using observed information only. Finally, longitudinal analyses provide evidence for a positive inter–temporal correlation between item nonresponse and any kind of subsequent nonresponse.* We are grateful to two anonymous referees and to Jan Goebel for very helpful comments and suggestions on an earlier draft of this paper. The paper also benefited from discussions with seminar participants at the Workshop on Item Nonresponse and Data Quality in Large Social Surveys, Basel/CH, October 9–11, 2003.     

Good item or bad—can latent class analysis tell?: the utility of latent class analysis for the evaluation of survey questions

Summary.  Latent class analysis has been used to model measurement error, to identify flawed survey questions and to estimate mode effects. Using data from a survey of University of Maryland alumni together with alumni records, we evaluate this technique to determine its usefulness for detecting bad questions in the survey context. Two sets of latent class analysis models are applied in this evaluation: latent class models with three indicators and latent class models with two indicators under different assumptions about prevalence and error rates. Our results indicated that the latent class analysis approach produced good qualitative results for the latent class models—the item that the model deemed the worst was the worst according to the true scores. However, the approach yielded weaker quantitative estimates of the error rates for a given item.