As part of the Administration for Children and Families, Office of Planning, Research and Evaluation-funded Early Head Start Family and Child Experiences Survey project, Mathematica updated a 2003 report containing resources to help Head Start programs for infants and toddlers develop a performance measurement plan and carry out data collection to support continuous program improvement. The report discusses the importance and development of a comprehensive plan and presents profiles of potentially useful instruments. This version updates 16 of the original profiles with new information about norms and test characteristics and adds 13 new profiles of more widely used measures.