Measure twice, cut once: attachment theory and the NICHD Study of Early Child Care and Youth Development.

The NICHD Early Child Care Research Network has produced research findings that provide reassuring confirmation of some central tenets of attachment theory, challenges to other aspects of the theory, and above all highlight the need for attachment researchers to clarify the claims for which the theory can be held accountable. This commentary on Friedman and Boyle's excellent review evaluates the strengths and weaknesses of the NICHD Study of Early Child Care and Youth Development as a study of attachment, and highlights the relevance of these findings for understanding the origins and consequences of attachment security, the problem of heterotypic continuity of the attachment construct, the importance of examining mediators and moderators of the developmental influence of security, and the interpretation of modest effect sizes from the study.