This report develops a strategy for improving national and state forecasts of future teacher attrition rates. The authors (1) develop a theory of teacher attrition that accounts for the disparate reasons for attrition and explains the patterns of attrition unique to each life cycle and career stage; (2) selectively review existing literature on teacher attrition and present attrition patterns from several states in order to test hypotheses deriving from their theory; (3) review the data available to support improved attrition models and recommend ways to make better use of the data; and (4) identify sampling and data collection strategies that will improve the value of data collected in a future national survey of teachers.