School vouchers and academic performance: results from three randomized field trials

This article examines the effects of school vouchers on student test scores in New York, New York, Dayton, Ohio, and Washington, DC. The evaluations in all three cities are designed as randomized field trials. The findings, therefore, are not confounded by the self‐selection problems that pervade most observational data. After 2 years, African Americans who switched from public to private school gained, relative to their public‐school peers, an average of 6.3 National Percentile Ranking points in the three cities on the Iowa Test of Basic Skills. The gains by city were 4.2 points in New York, 6.5 points in Dayton, and 9.2 points in Washington. Effects for African Americans are statistically significant in all three cities. In no city are statistically significant effects observed for other ethnic groups, after either 1 or 2 years. © 2002 by the Association for Policy Analysis and Management.     

The Road from Communal to Owned Housing

Homes in China have transitioned during the past sixty years from government-allocated to commercial housing. The change has brought immense improvements to people＇s living conditions.     

上市公司会计舞弊的演化博弈分析

在对上市公司会计舞弊研究的文献进行综述的基础上,从舞弊者之间竞争角度出发,量化舞弊三角理论,构建三个鹰鸽演化博弈模型,解出舞弊演化路径及均衡点,竞争者舞弊与否不仅受舞弊的预期成本影响,还受评价标准高低的影响,当舞弊成本较低时,博弈双方可能都舞弊,但舞弊成本很高时,受评价标准影响,仍然存在舞弊的可能.     

The National Partnership for Environmental Priorities Program

The National Partnership for Environmental Priorities (NPEP) program was created by the U.S. Environmental Protection Agency (USEPA) to reduce or eliminate the nation's production of hazardous wastes and products. The NPEP is a voluntary program that provides incentives to public, private, and federal organizations that minimize their use and generation of thirty-one priority chemicals. These chemicals are considered to be persistent, bioaccumulative, and toxic in the environment and present health risks to human and ecological receptors. The USEPA estimates that 90 percent of priority chemicals are used or produced during manufacturing of various household and industrial products and, as a result, end up in municipal and industrial waste streams. Ultimately, these chemicals find their way back into the environment through wastewater discharges, incineration, or other disposal practices. The NPEP program supports the goals of the National Waste Minimalization Program by encouraging simple waste minimalization solutions such as recycling, replacement, or elimination of wastes or products that contain priority chemicals, and cradle-to-cradle management of waste. Although the USEPA does not limit waste minimalization practices to only the priority chemicals, the program has set specific goals to track the elimination of these thirty-one chemicals to the environment on an annual basis.