【文章內(nèi)容簡介】 e efficacy of valueadded approaches for assessing teacher quality. In a review of studies that utilize valueadded modeling to explain teacher effects on student achievement, McCaffrey et al. concluded that while the valueadded approach has limitations it nonetheless should be an alternative in examining teacher quality. They stated, “…given the current state of knowledge about VAM [valueadded modeling] we expect that some efforts to estimate teacher effects could provide useful information on teachers” . The overarching finding from valueadded studies is that effective teachers are, indeed, essential for student success. For example, Wright et al. found there is evidence that lowerachieving students are more likely to be placed with less effective teachers. Thus, the neediest students are being instructed by the least capable teachers. Using a multiyear database, Sanders and colleagues found that when children, beginning in third grade, were placed with three high performing teachers in a row, they scored, on average, at the 96th percentile on Tennessee’s statewide mathematics assessment at the end of fifth grade. When children with parable achievement histories starting in third grade were placed with three low performing teachers in a row, their average score on the same mathematics assessment was at the 44th percentile, yielding a 52percentile point difference. Qualities of Effective TeachersDimensions that characterize teacher effectiveness synthesized from a metareview of extant research were used as the conceptual framework for this study. From this review, the qualities of effective teachers were divided into the dimensions of instructional expertise, student assessment, learning environment, and personal qualities of the teacher (Table 1). 2 Method Part I: Identification of Effective Teachers Setting and Target PopulationThe data for the current study were collected from third grade students and teachers in a moderately sized urban school district located in Virginia. The school district has 36 schools, a student population of approximately 23,000, and a teacher population of nearly 1,500. The student population is predominantly 60% African American and 35% white。 approximately 2% of the student population receives ESL services. The sample selected for this study consisted of the third grade regular classroom teachers and students in the school district. Data for 1936 students and 85 classrooms were used for the analyses. Identifying Teacher EffectivenessThe methodology used for determining teacher effectiveness for the study relied on the assumption that effective teachers are those who foster achievement gains beyond that expected from the student’s past achievement. This methodology is similar to other valueadded systems that have been in use for some time . The methodology employed was both ordinary least squares (OLS) and hierarchical linear modeling (HLM). Part II: Comparative Analysis of Effective and Less Effective Teachers SamplePart II of the study involved an examination of the instructional practices of teachers who effected higher than predicted gains in student learning and those who effected lower than predicted gains in student learning as measured by the SOL assessments. In order to explore the phenomenon of effective teaching, exploratory crosscase analyses were used. The results of part I were used to identify thirdgrade teachers for indepth case studies from among the highest and lowest quartiles based on their student academic growth posite. Data Analysis ApproachIn order to explore the phenomenon of effective teaching, the qualitative approach of exploratory crosscase analysis was used. Using multiple cases makes it possible to build a logical chain of evidence. Additionally, crosscase analysis allows for analysis of consistencies identified across the cases . InstrumentationSpecifically, the following in