Research Findings: Aiming to raise the quality of early childhood teachers and caregivers and to reduce turnover, government and professional associations are pursuing 2 intervention strategies. The 1st mandates higher credential levels, as seen with Head Start and state preschool reforms. Here we examine the efficacy of the 2nd strategy: offering wage incentives to encourage in-service training and to reduce job turnover. We followed 2,783 preschool center directors, teachers, and classroom aides who participated in California's Child-care Retention Incentive (CRI) program during a 3-year period. County-designed programs offered differing combinations of wage supplements and professional development to participants who pursued college-level training. We found a priori low levels of staff turnover among those who selected into the CRI program. This conditioned the modest program effects that we observed and revealed the segmented character of the early childhood labor force, which appears to shape selection patterns. Demographic attributes of staff and the auspice in which staff worked were significantly related to the number of college units acquired and to job stability. Specific features of local CRI programs were less influential. Staff completed more college courses when participating in programs that provided stronger career advising and professional activities in addition to their college coursework. Practice or Policy: Implications for incentive programs nationwide are discussed. (Contains 3 footnotes, 5 tables, and 2 figures.)