Grader Bias in Cattle Markets? Evidence from Iowa
利用2000-2002年中西部分割厂的样本数据，检验美国农业部肉牛分级员是否存在系统性偏见，发现分级标准在不同工厂间差异显著，且对低质量胴体的分级更准确。
Abstract Live cattle are increasingly priced as an explicit function of U.S. Department of Agriculture yield and quality grades. Human graders visually inspect each slaughtered carcass and call grades in a matter of seconds as the carcass passes on a moving trolley. We examine whether there is systematic bias in grade calls using a sample of loads delivered to three different midwestern packing plants during 2000–2002. Overall, results indicate that indeed there is a bias, and that grading standards vary significantly across packing plants. Results also are consistent with a behavioral model where graders are more accurate when grading relatively low‐quality carcasses.