Homework doesn\'t do much for math and science students\' grades, though standardized test scores improve, U.S. researchers say they found. Adam Maltese, assistant professor of science education in the Indiana University School of Education, Robert H. Tai, associate professor of science education at the Curry School of Education at the University of Virginia, and Xitao Fan, dean of education at the University of Macau, examined survey and transcript data of more than 18,000 10th-grade students to uncover explanations for academic performance. The data focused on individual classes for students, examining the outcomes via the transcripts for students from two nationwide samples collected in 1990 and 2002 by the National Center for Education Statistics. The study, published in The High School Journal, found contrary to previous published research, a regression analysis of time spent on homework and the final class grade found no substantive difference in grades between students who complete homework and those who did not. However, the analysis found a positive association between student performance on standardized tests and the time they spent on homework. The researchers indicated the types of homework assignments typically given might work better toward standardized test preparation than for retaining knowledge of class material.