This article draws on results of an evaluation of Sure Start activities in an area of South Wales in 2004, focusing in particular on measurements of improvements to child development and measurements of benefits to parents. The article reports on the methods that were used to collect relevant data and examines the problems associated with linking these data to effectiveness. The observed examples of good practice were not fully reflected in the data and documentary evidence submitted by projects for evaluation purposes. Pre-intervention and post-intervention assessments of child development did demonstrate some positive change, but the tools used were not robust. They did not allow for other influencing factors such as parenting skills, or show an equal assessment of all areas of development. Attempts were made to record parent satisfaction but they did not identify the level of satisfaction that was apparent in observation and in discussion with parents during the evaluation. It is argued that an adaptation of practice to a professional/parent partnership model would facilitate this and could encourage active parent participation in Sure Start management. At the same time it would provide parents with increased skills and confidence that would be of future benefit to them and their children in future years, beyond the scope of Sure Start. (Contains 2 tables.)