“These findings answer the first research question in the negative and the second in the affirmative. The large-scale data do seem to confirm some of the findings from small-scale research but not others. Some practices, namely metacognition, using trade books and a measure of integrating reading and writing, did prove positively related to reading comprehension. Other practices, however, such as having students work in groups, increasing parental involvement, and the use of authentic assessment, did not. And time spent reading in class actually had a negative relationship to student performance. The addition of classroom practices to large-scale models seems to make the overall impact of teachers comparable to that of student background. As with typical production functions, the teacher background model revealed only a single modest teacher effect. The classroom practice model, however, revealed multiple teacher effects, some of them quite strong. The total standardized effect for the four teacher variables (.70) is actually somewhat larger than the total standard effect of the two student background measures (.56).” Results sect. 5th para.