There is increasing agreement among researchers and policymakers that teachers vary widely in their ability to improve student achievement, and the difference between effective and ineffective teachers has substantial effects on standardized test outcomes as well as later life outcomes. However, there is not similar agreement about how to improve teacher effectiveness. Several research studies confirm that on average novice teachers show remarkable improvement in effectiveness over the first five years of their careers. In this paper we employ rich data from New York City to explore the variation among teachers in early career returns to experience. Our goal is to better understand the extent to which measures of teacher effectiveness during the first two years reliably predicts future performance. Our findings suggest that early career returns to experience may provide useful insights regarding future performance and offer opportunities to better understand how to improve teacher effectiveness. We present evidence not only about the predictive power of early value-added scores, but also on the limitations and imprecision of those predictions.