Abstract
This issue comprises a comprehensive overview of contribution analysis (CA), one of the newer approaches to evaluation within the ‘theory-based’ or informed evaluation family. John Mayne, the eminent originator of CA, agreed not only to guest-edit this Special Issue but also to reflect on his latest thinking about the future direction that CA might take. In a world where calls for greater accountability and transparency continue to strengthen demands for ‘impact’ evaluations, the ideas in this issue are likely to prove both a timely and valuable input to some of the most pressing debates in which evaluators are nowadays engaged.