Researchers know that prekindergarten offers short term benefits - kids do better in the early grades if they've gone to Pre-K. But the effects seem to fade by about the third grade. In this episode: new research into this fade out effect.

Researchers paired student data from a statewide Pre-K experiment with records of teacher observation scores from Tennessee's new formal evaluation program. Their idea was a simple one - would a student's access to high-quality early grade teachers help the Pre-K effects last longer?

Guest: Walker Swain, University of Georgia

Guest Host: Anna Gassman-Pines, Duke Center for Child & Family Policy