Virtually No Effect? Different Uses of Classroom Computers and their Effect on Student Achievement

Most studies find little to no effect of classroom computers on student achievement. We suggest that this null effect may combine positive effects of computer uses without equivalently effective alternative traditional teaching practices and negative effects of uses that substitute more effective teaching practices. Our correlated random effects models exploit within‐student between‐subject variation in different computer uses in the international TIMSS test. We find positive effects of using computers to look up information and negative effects of using computers to practice skills, resulting in overall null effects. Effects are larger for students with high socioeconomic status and mostly confined to developed countries.     

Motivations and barriers of foreign R&D activities in China

The continued growth of the Chinese economy accompanied with the expansion of international investment in China has led to an increase in foreign research and development (R&D) activities in the country. Aside from the rising importance of R&D internationalization, research on foreign R&D in China has been neglected in the past due to its emerging status. In this article we examine drivers and barriers for conducting R&D in China. The focus of our research is on transnational companies typically characterized by decentralized R&D activities. Our research is mainly based on qualitative interviews with senior R&D managers. The success of foreign R&D activities in China strongly depends on the realistic estimation of its advantages and the proper identification and handling of barriers.     

Combining information for prediction in linear regression

This article deals with the prediction problem in linear regression where the measurements are obtained using k different devices or collected from k different independent sources. For the case of k=2, a Graybill-Deal type combined estimtor for the regression parameters is shown to dominate the individual least squares estimators under the covariance criterion. Two predictors ŷ _c and ŷ _p are proposed. ŷ _c is based on a combined estimator of the regression coefficient vector, and ŷ _p is obtained by combining the individual predictors from different models. Prediction mean square errors of both predictors are derived. It is shown that the predictor ŷ _p is better than the individual predictors for k≥2 and the predictor ŷ _c is better than the individual predictors for k=2. Numerical comparison between ŷ _c and ŷ _p shows that the former is superior to the latter for the case k=2.     

The Economic Forces Driving Food Safety Quality in Meat and Poultry

This article examines the impact of regulation and market-driven private actions on food safety performance in the meat and poultry industries. We find that private actions account for about 80% and regulation about 20% of the overall reduction in the share of samples of cattle and hog carcasses, ground beef, and broilers testing positive for Salmonella if all regulation and private actions were increased by identical amounts.     

Comparative Advantage in Demand: Experimental Evidence of Preferences for Genetically Modified Food in the United States and European Union

The United States (US) exports more than US$6 billion in agricultural commodities to the European Union(EU) each year, but one issue carries the potential to diminish this trade: use of biotechnology in food production. The EU has adopted more stringent policies towards biotechnology than the US. Understanding differences in European and American policies towards genetically modified (GM) foods requires a greater understanding of consumers’ attitudes and preferences. This paper reports results from the first large‐scale, cross‐Atlantic study to analyse consumer demand for genetically modified food in a non‐hypothetical market environment. We strongly reject the frequent if convenient assumption in trade theory that consumer preferences are identical across countries: the median level of compensation demanded by English and French consumers to consume a GM food is found to be more than twice that in any of the US locations. Results have important implications for trade theory, which typically focuses on differences in specialization, comparative advantage and factor endowments across countries, and for on‐going trade disputes at the World Trade Organization.     

The Lowry Model Revisited: Incorporating a Multizonal Input-Output Model into an Urban Land Use Allocation Model

This paper formulates a new generation of Lowry-style models that combine a multizonal input-output model and an urban land use allocation model. Three different types of models are proposed: 1) an unconstrained model, 2) a primal of a linear programming approach that includes land supply constraints, and 3) a modified dual of the linear programming approach that allocates land based on additional conditions of economic efficiency. The modified dual formulation improves upon the limitations of Lowry models and their derivatives. First, the proposed model has sound theoretical underpinnings that incorporate the production theory of input-output models and the behavioral theory of optimization models. Second, the proposed model allocates land on the basis of economic efficiency by imposing a procedure that equalizes shadow prices. And third, the proposed model is an optimization model that fully accounts for the spatial and sectoral relationships of multiplier effects determining land use demand.     

Integration of collective bargaining and formal worker participation processes: Boon or barrier to worker rights?

Many employers are extending workplace rights by allowing for more employee voice in decision making. Numerous unionized organizations have established formal worker participation processes to help achieve this end and to improve organizational performance. Based largely on theory, such processes are normally designed to operate independently from the bargaining process. The purpose of this study was to examine the relationship between participation and bargaining processes, and the effect of this relationship on workplace satisfaction. A total of 712 Midwest union officials were surveyed, and the results indicate that the processes tend to become integrated in the workplace. Further, union officials' workplace satisfaction was greater where formal worker participation is institutionalized within the bargaining process.