It is noted, however, that structural indicators of an ECEC program and caregiver characteristics contribute to the overall quality or child developmental outcomes through relatively indirect ways compared to process features (Vandell & Wolfe, 2000). For example, Blau (2000) proposes a twostage model, suggesting that structural features contribute to the process quality in ECEC settings during the first stage, which subsequently affects children’s developmental outcomes. Similarly, Phillipsen, Burchinal, Howes and Cryer (1997) suggest that the effects of structural variables on 15 The Campbell Collaboration | www.campbellcollaboration.org child developmental outcomes are mediated by process quality (e.g., more nurturing and extensive teacher-child interactions)