What Makes a Difference

John M. Love, Ph.D., retired as senior fellow at Mathematica Policy Research in 2010 and now provides consultation on program evaluation and early childhood policy issues to state and county agencies. He is president of the Ashland Institute for Early Childhood Science and Policy. In addition to directing the Early Head Start national evaluation contract from his inception, he has studied Head Start, preschool, and child care programs since the early 1970s.Rachel Chazan-Cohen, Ph.D., is Associate Professor of Applied Developmental Psychology at George Mason University. Previously, she was the coordinator of infant and toddler research in theOffice of Planning,Research, and Evaluation in the Administration for Children and Families, U.S. Department of Health and Human Services. She is particularly interested in the biological, relational, and environmental factors influencing the development of at-risk children, and most especially, on the creation, evaluation, and refinement of intervention programs for families with infants and toddlers. Helen Raikes, Ph.D., is Willa Cather Professor and Professor, Child, Youth and Family Studies, University of Nebraska-Lincoln. Her research has focused on infants, toddlers and preschool age children at greatest risk, early language and social emotional development, and on parenting with an emphasis on understanding influences on the developmental trajectories of vulnerable children that are amenable to intervention. Another strand of research focuses on state and federal programs and policies that affect young children's developmental outcomes. She was a SRCD Social Policy Fellow at the Administration on Children, Youth and Families when the Early HeadStart Research and Evaluation Study began.Jeanne Brooks-Gunn, Ph.D. is the Virginia and Leonard Marx Professor of Child Development and Education at Teachers College and the College of Physicians and Surgeons at Columbia University, and she directs the National Center for Children and Families (www.policyforchildren.org). She is interested in environmental, biological, and psychological factors that contribute to children's well-being. She is a member of the Institute of Medicine of the National Academies and the National Academy of Education. She has received the policy award from SRCD and was co-editor of their Social Policy Report.

• I. BACKGROUND LITERATURE REVIEW PERTAINING TO THE EARLYHEAD START STUDYHelen H. Raikes, Jeanne Brooks-Gunn, and John M. LoveII. DESIGN AND METHODS IN THE EARLY HEAD START STUDYRichard A. Faldowski, Rachel Chazan-Cohen, John M. Love, and Cheri VogelIII. IMPACTS OF EARLY HEAD START PARTICIPATION ON CHILD AND PARENTOUTCOMES AT AGES 2, 3, AND 5Cheri Vogel, Jeanne Brooks-Gunn, Anne Martin, and Mary M. KluteIV. FAMILY SUBGROUPS AND IMPACTS AT AGES 2, 3, AND 5: VARIABILITY BY RACE/ETHNICITY AND DEMOGRAPHIC RISKHelen H. Raikes, Cheri Vogel, and John M. LoveV. PROGRAM SUBGROUPS: PATTERNS OF IMPACTS FOR HOME-BASED, CENTER-BASED, AND MIXED-APPROACH PROGRAMSRachel Chazan-Cohen, Helen H. Raikes, and Cheri VogelVI. LINKS BETWEEN EARLY CARE AND EDUCATION EXPERIENCES BIRTH TO AGE 5 AND PREKINDERGARTEN OUTCOMESRachel Chazan-Cohen and Ellen E. KiskerVII. CONCLUSIONS AND IMPLICATIONSJeanne Brooks-Gunn, John M. Love, Helen H. Raikes, and Rachel Chazan-CohenREFERENCESACKNOWLEDGMENTSCONTRIBUTORSSTATEMENT OF EDITORIAL POLICYSUBJECT INDEX