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Value-added models in education research allow researchers to explore how a wide variety of policies and measured school inputs affect the academic performance of students. The impacts of such interventions are typically quantified in terms of effect sizes. We estimate the overall extent of test measurement error and how this varies across students using the covariance structure of student test scores across grades in New York City from 1999 to 2007. Results reinforce the importance of accounting for measurement error, as it meaningfully increases effect size estimates associated with teacher attributes. There are important differences in teacher effectiveness that are systematically related to observed teacher attributes. Such effects are important in the formulation and implementation of personnel policies.
Citation: Donald Boyd, Pamela Grossman, Hamilton Lankford, Susanna Loeb, James Wyckoff (2008). Measuring Effect Sizes: The Effect of Measurement Error. CALDER Working Paper No. 19
This brief describes estimation and measurement issues relevant to estimating the quality of instruction in the context of a cumulative model of learning. The discussion highlights the importance of accounting for student differences and the advantages of focusing on student achievement gains as opposed to differences in test scores.
Most studies that have fueled alarm over the attrition and mobility rates of high-quality teachers have relied on proxy indicators of teacher quality, which recent research finds to be only weakly correlated with value-added measures of teachers' performance. We examine attrition and mobility of teachers using teacher value-added measures for early-career teachers in North Carolina public schools from 1996 to 2002. Our findings suggest that the most-effective teachers tend to stay in teaching and in specific schools. Contrary to common expectations, we do not find that more-effective teachers are more likely to leave more-challenging schools.
Citation: Dan Goldhaber, Betheny Gross, Daniel Player (2007). Are Public Schools Really Losing Their Best? Assessing the Career Transitions of Teachers and Their Implications for the Quality of the Teacher Workforce. CALDER Working Paper No. 12
One of the first papers to ever estimate teacher effects at the secondary school level, this groundbreaking work presents evidence that teacher credentials affect secondary school student success in systematic ways and to a significant, policy-relevant extent. We use data on statewide end-of-course tests in North Carolina to examine the relationship between teacher credentials and student achievement at the high school level. We find compelling evidence that teacher credentials affect student achievement in systematic ways and that the magnitudes are large enough to be policy relevant. As a result, the uneven distribution of teacher credentials by race and socio-economic status of high school students- a pattern we also document- contributes to achievement gaps in high school.
Citation: Charles Clotfelter, Helen Ladd, Jacob Vigdor (2007). Teacher Credentials and Student Achievement in High School: A Cross-Subject Analysis with Student Fixed Effects. CALDER Working Paper No. 11
This paper explores how the distribution of teacher qualifications and student achievement in New York City have changed from 2000 through 2005 using data on teachers and students. We find: the gap between the qualifications of New York City teachers in high-poverty schools and low-poverty schools has narrowed substantially over this period, and that this gap-narrowing associated with new hires has been driven almost entirely by the substitution of teachers entering through alternative certification routes, for uncertified teachers in high-poverty schools, these changes resulted from a direct policy intervention eliminating unlicensed teachers, and perhaps most intriguing, much larger gains could result if teachers with strong teacher qualifications could be recruited.
Citation: Donald Boyd, Hamilton Lankford, Susanna Loeb, Jonah Rockoff, James Wyckoff (2007). The Narrowing Gap in New York City Teacher Qualifications and Its Implications for Student Achievement in High Poverty Schools. CALDER Working Paper No. 10
This paper explores the relationship between teacher testing and teacher effectiveness using a unique dataset that links teachers to their individual students. My findings show a positive relationship between some teacher licensure tests and student achievement. But they also suggest that states face significant tradeoffs when they require particular performance levels as a precondition to becoming a teacher: some teachers whom we might wish were not in the teacher workforce based on their contribution toward student achievement are eligible to teach based on their performance on these tests, while other individuals who would be effective teachers are ineligible.
Citation: Dan Goldhaber (2007). Everyone's Doing It, but What Does Teacher Testing Tell Us about Teacher Effectiveness?. CALDER Working Paper No. 9
This study considers the efficacy of a certification system for teachers established by the National Board for Professional Teaching Standards (NBPTS). The authors utilize a four-year span of the longitudinal data from Florida to determine the relationship between teacher NBPTS certification and student test scores on low-stakes and high-stakes exams. They find evidence that NBPTS certification provides a positive signal of teacher productivity in some cases, but it is highly variable. The process of becoming NBPTS certified does not appear to increase teacher productivity nor do NBPTS-certified teachers appear to enhance the productivity of their colleagues.
Citation: Douglas Harris, Tim Sass (2007). The Effects of NBPTS-Certified Teachers on Student Achievement. CALDER Working Paper No. 4
Using longitudinal data from the state of Florida, this study examines the effects of various types of education and training on the ability of teachers to promote student achievement. It suggests that teacher training generally has little influence on productivity. One exception is that content-focused teacher professional development is positively associated with productivity in middle and high school math. In addition, more experienced teachers appear more effective in teaching elementary and middle school reading. There is no evidence that either pre-service (undergraduate) training or the scholastic aptitude of teachers influences their ability to increase student achievement.
Citation: Douglas Harris, Tim Sass (2007). Teacher Training, Teacher Quality and Student Achievement. CALDER Working Paper No. 3
In this paper, the authors use a ten-year span of longitudinal data from North Carolina to explore a range of questions related to the relationship between teacher characteristics and credentials, on the one hand, and student achievement on the other. They conclude that a teacher's experience, test scores and regular licensure all have positive effects on student achievement, with larger effects for math than for reading. Taken together the various teacher credentials exhibit quite large effects on math achievement, whether compared to the effects of changes in class size or to the socio-economics characteristics of students.
Citation: Charles Clotfelter, Helen Ladd, Jacob Vigdor (2007). How and Why Do Teacher Credentials Matter for Student Achievement?. CALDER Working Paper No. 2
The central question for this study is how the quality of the teachers and principals in high poverty schools in North Carolina compares to that in the schools serving more advantaged students. A related question is why these differences emerge. The consistency of the patterns across many measures of qualifications for both teachers and principals leaves no doubt that students in the high poverty schools are served by school personnel with lower qualifications than those in the lower poverty schools. Moreover, in many cases the differences are large. Additional evidence documents that the differences largely reflect predictable outcomes of the labor market for teachers and principals.
Citation: Charles Clotfelter, Helen Ladd, Jacob Vigdor, Justin Wheeler (2007). High Poverty Schools and the Distribution of Teachers and Principals. CALDER Working Paper No. 1