The review authors thank the many people who commented on the project protocol and Cochrane protocol and review at various stages, helping to make it feasible. In particular this includes the 1998 consumer advisory group established for this review by the Cochrane Consumers and Communication Review Group (comprising Hilda Bastian and Genny Nolan (Australia), Teenah Handiside (New Zealand), and Christine Brunswick (USA)); Professors Theresa Marteau (University of London) and Alex Barratt (University of Sydney) for discussions about screening programmes; Silvana Unigwe (medical student) for work on the previous version of the review; the Contact Editor Dominique Broclain, the editors of the Cochrane Consumers and Communication Review Group, Review Group Coordinator Megan Prictor, Coordinating Editor Sophie Hill, former Trials Search Coordinator Judy Stoelwinder, and external peer reviewers. We gratefully acknowledge the financial support from the Cochrane Health Promotion and Public Health Field which enabled completion of the first published version of this review in 2003 (Edwards 2003c) and the UK Department of Health for its support (via the Review Group) to speed up completion of the updated review in 2006.