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Using administrative longitudinal data from five states, we study how value-added measures of teacher performance are affected by changes in state standards and assessments. We first document the stability of teachers' value-added rankings during transitions to new standard and assessment regimes and compare our findings to stability during stable standard and assessment regimes. We also examine the predictive validity of value-added estimates during nontransition years over transition-year student achievement. In most cases we find that measures of teacher value added are similarly stable in transition years and nontransition years. Moreover, there is no evidence that the level of disadvantage of students taught disproportionately influences teacher rankings in transition years relative to stable years. In the states we study, student achievement in math can consistently be forecasted accurately--although not perfectly--using value-added estimates for teachers during stable standards and assessment regimes. There was somewhat less consistency in reading, because we find cases where test transitions significantly reduced forecasting accuracy.

A sizeable body of evidence has documented the effectiveness of Teach For America (TFA) corps members at raising the mathematics test scores of their students, though little is known about the program's impact at the school level. TFA's recent placement strategy in the Miami-Dade County Public Schools, in which large numbers of TFA corps members are placed as clusters into a targeted set of disadvantaged schools, provides an opportunity to evaluate the impact of the TFA program on broader school performance. This study examines whether the influx of TFA corps members led to a spillover effect on other teachers' performance. We find that many of the schools chosen to participate in the cluster strategy experienced large subsequent gains in mathematics achievement. These gains were driven in part by the composition effect of having larger numbers of effective TFA corps members. However, we do not find any evidence that the clustering strategy led to any spillover effect on schoolwide performance. In other words, our estimates suggest that the extra student gains for TFA corps members under the clustering strategy would be equivalent to gains resulting from an alternate placement strategy in which corps members were evenly distributed across schools.

This paper examines whether teachers in schools serving students from high-poverty backgrounds are as effective as teachers in schools with more advantaged students. The question is important. Teachers are recognized as the most important school factor affecting student achievement, and the achievement gap between disadvantaged students and their better off peers is large and persistent. Using student-level microdata from 2000-2001 to 2004-2005 from Florida and North Carolina, the authors compare the effectiveness of teachers in high-poverty elementary schools (greater than 70% FRL students) with that of teachers in lower-poverty elementary schools (less than 70% FRL students). The results show that the average effectiveness of teachers in high-poverty schools is in general less than teachers in other schools, but only slightly, and not in all comparisons. The authors also find differences in within-school-type variation in teacher effectiveness in nearly every comparison. These differences are largely driven by the longer tail at the bottom of the teacher effectiveness distribution in high-poverty schools. Teachers at the top of the effectiveness distribution are very similar across school settings. The observed differences in teacher quality between high-poverty and lower-poverty schools are not due to differences in the observed characteristics of teachers, such as experience, certification status and educational attainment. Rather, they appear to arise from differences in the marginal return or payoff from increases in a characteristic. In particular, the gain in productivity from increased experience is much stronger in lower-poverty schools. The lower return to experience in high-poverty schools does not appear to be a result of differences in the quality of teachers who leave teaching or who switch schools. Rather, it may be the case that the effect of experience on teacher productivity may depend on the setting in which the experience is acquired. If there are positive spillovers among teachers that depend on teacher quality (ie. teacher "peer effects") or if exposure to challenging student populations lessens the future productivity of teachers (i.e. leads to "burn out"), teachers in schools serving large proportions of low-income students may simply not improve much as time goes by. These findings suggest that solutions to the achievement gap between high and lower-poverty schools may be complex. Changing the quality of new recruits or importing teachers with good credentials into high-poverty schools may not be sufficient. Rather, the findings suggest that measures that induce highly effective teachers to move to high-poverty schools and which promote an environment in which teachers' skills will improve over time are more likely to be successful. An appendix is included. (Contains 8 figures, 15 tables and 14 footnotes.) [This is an updated version of Working Paper 41.]

This research investigates the relative effectiveness (in terms of student tested achievement) of Teach for America (TFA) teachers, and examines the validity of the criticisms of TFA. Specifically, the authors look at TFA teachers in secondary schools, and especially in math and science, where considerable program growth is planned over the next few years. Using individual level student data linked to teacher data in North Carolina, the authors estimate the effects of having a TFA teacher compared to a traditional teacher on student performance. The North Carolina data they employ are uniquely suited for this type of analysis because it includes end of course (EOC) testing for students across multiple subjects. This allows them to employ statistical methods that attempt to account for the nonrandom nature of student assignments to classes/teachers, which have been shown to lead to biased estimates of the impact of teacher credentials (Clotfelter, Ladd, and Vigdor, 2007a; Goldhaber, 2007). The findings show that TFA teachers are more effective, as measured by student exam performance, than traditional teachers. Moreover, the authors suggest that the TFA effect, at least in the grades and subjects investigated, exceeds the impact of additional years of experience, implying that TFA teachers are more effective than experienced secondary school teachers. The positive TFA results are robust across subject areas, but are particularly strong for math and science classes. An appendix is included. (Contains 1 figure, 12 tables, 1 exhibit and 14 footnotes.) [This report was supported by the Steven L. Merrill Family Foundation.]