At the forefront of debates about early childhood education policy is a focus on raising the quality of learning environments in community-based centers and schools as a means of promoting child development, particularly for low-income children and children of color. Central to this discussion is how policymakers and practitioners can promote the quality of teachers’ professional practice in early childhood classrooms and support the workforce through ongoing professional development. Much more needs to be learned to inform practice and policy regarding what works, and for whom, when promoting quality in early childhood education.

First, there is more to learn about which specific teacher practices best support child outcomes. Evidence  shows that process quality — the quality of teacher-child interactions — is more strongly associated with child outcomes than structural quality — the way classrooms are configured. Less work has focused on the degree to which specific teacher practices related to instructional quality or to particular content domains are associated with child outcomes. Second, experimental research suggests that both teacher training and ongoing coaching are related to improved classroom practice, but it is unclear how much professional development a typical teacher receives or how the level of professional development is related to observed teacher practice. Finally, growing cultural and linguistic diversity in today’s classrooms highlights a need to examine not only which teacher practices matter but also which practices may be more supportive for different subgroups of children. Few empirical studies have examined whether the association between classroom quality and child outcomes varies for children from different subgroups; replication is needed.

What Matters Most for Teachers and Young Children? An Examination of Teacher Practices, Child Outcomes, and Teacher Professional Development in Low-Income Preschool Programs is a secondary data analysis that tackles these questions head-on by examining (a) which specific teacher practices matter for supporting child outcomes, (b) which teacher practices matter for whom, (c) how teacher practices are related to teacher professional development, and (d) patterns in teacher practices, focusing on curriculum implementation.