Non-experimental value-added models have been shown to yield forecast-unbiased estimates of teacher and school effects. To investigate, we propose a dynamic state-space model of knowledge accumulation, in which test scores are imperfect measures of knowledge, and students receive temporary and persistent shocks to their stock of knowledge each…

Until recently, legal challenges to using value-added models (VAMs) throughout the United States (US) for high-stakes teacher evaluative decisions (e.g., merit pay, tenure, and termination) were unsuccessful, especially in the state of Florida. Hence, prior and still, multiple teachers throughout Florida have been terminated or involuntarily…

Ongoing or recently completed across the United States are a series of lawsuits via which teacher plaintiffs are contesting how they are being evaluated using value-added models (VAMs) as part of states'/districts' teacher accountability systems. To investigate the empirical and pragmatic matters addressed in court, researchers conducted a case…

Background: Educational and developmental psychologists often examine how groups change over time. Two analytic procedures -- analysis of covariance (ANCOVA) and the gain score model -- each seem well suited for the simplest situation, with just two groups and two time points. They can produce different results, what is known as Lord's paradox.…

Inappropriate treatment of missing data may introduce bias into the value-added estimation. We consider a commonly used value-added model (VAM), which includes the past student test score as a covariate. We formulate a joint model of student achievement and missing data, in which the probability of observing a test score depends on observing the…

Recent lawsuits reveal common mistakes plaguing current teacher evaluation systems. Drawing on arguments in court documents for prominent cases, the authors find that evaluation systems using value-added measures (VAM) suffer from a) inconsistent and unreliable teacher ratings, b) bias toward and against teachers of certain types of students, c)…

By aggregating residual gain scores (the differences between each student's current score and a predicted score based on prior performance) for a school or a teacher, value-added models (VAMs) can be used to generate estimates of school or teacher effects. It is known that random errors in the prior scores will introduce bias into predictions of…

Contemporary teacher evaluation systems are built upon multiple measures including, primarily, teacher-level value-added and observational estimates. While researchers have conducted examinations of these systems and indicators, researchers have not investigated how using these systems might distort the validity of the inferences being drawn,…

State and federal accountability policies are predicated on the ability to estimate valid and reliable measures of school impacts on student learning. The typical spring-to-spring testing window potentially conflates the amount of learning that occurs during the school year with learning that occurs during the summer. We use a unique dataset to…

Estimates of teacher "value-added" suggest teachers vary substantially in their ability to promote student learning. Prompted by this finding, many states and school districts have adopted value-added measures as indicators of teacher job performance. In this paper, we conduct a new test of the validity of value-added models. Using…

We apply "value-added" models to estimate the effects of teachers on an outcome they cannot plausibly affect: student height. When fitting the relatively simple models that are widely used in educational practice to New York City data, we find the standard deviation of teacher effects on height is nearly as large as that for math and…

Being an expert involves explaining how things are supposed to work, and, perhaps more important, why things might not work as supposed. In this study, researchers surveyed scholars with expertise in value-added models (VAMs) to solicit their opinions about the uses and potential of VAMs for teacher-level accountability purposes (for example, in…

Value-added measures of educational progress have been used by education researchers and policy-makers to assess the performance of teachers and schools, contributing to performance-related pay and position in school league tables. They are designed to control for all underlying differences between pupils and should therefore provide unbiased…

Since 1992, the UK Government has published so-called "school league tables" summarising the average General Certificate of Secondary Education (GCSE) "attainment" and "progress" made by pupils in each state-funded secondary school in England. While the headline measure of school attainment has remained the percentage…

Estimates of teacher "value-added" suggest teachers vary substantially in their ability to promote student learning. Prompted by this finding, many states and school districts have adopted value-added measures as indicators of teacher job performance. In this paper, we conduct a new test of the validity of value-added models. Using…