Estimating teachers’ value-added effects using generalized persistence model

One of the issues in value-added assessment of teachers is the persistence of effects. Although Generalized Persistence (GP) model addresses this issue, it is not commonly used because of the difficulty interpreting its results. The purpose of this study is to examine teachers' value-added scores using the GP model and interpret the findings in terms of teacher assessment. Test scores of the same students (1432 students studying in 12 different middle schools) for three consecutive test administrations were used to estimate value-added scores of 61 science and 42 Turkish teachers. While correlation between current and future year value-added scores was high for science teachers (r = 0.88), it was lower for Turkish teachers (r = 0.46). On the other hand, the reliability of the estimates was found to be low. The study is concluded with suggestions for the use of the GP model and implications for further research and policy use.