Missouri

Teacher pension systems target retirements within a narrow range of the career cycle by penalizing individuals who separate too soon or remain employed too long. The penalties result in the retention of some teachers who would otherwise choose to leave, and the premature exit of some teachers who would otherwise choose to stay. We examine how the effects of teachers' pension incentives on workforce composition influence teacher quality. Teachers who are held in by the "pull" incentives in the pension systems are not more effective, on average, than the typical teacher.

We compare teacher preparation programs in Missouri based on the effectiveness of their graduates in the classroom. The differences in effectiveness between teachers from different preparation programs are very small. In fact, virtually all of the variation in teacher effectiveness comes from within-program differences between teachers. Prior research has overstated differences in teacher performance across preparation programs for several reasons, most notably because some sampling variability in the data has been incorrectly attributed to the preparation programs.

The specifics of how growth models should be constructed and used to evaluate schools and teachers is a topic of lively policy debate in states and school districts nationwide. In this paper we take up the question of model choice and examine three competing approaches. The first approach, reflected in the popular student growth percentiles (SGPs) framework, eschews all controls for student covariates and schooling environments.