This paper With thanks to my colleagues Janet Aucock (University of St Andrews Library) and Rosemary Stenson (University of Glasgow Library) for their comments and advice. describes a recent project by Research Libraries UK to analyse the ‘collective collection’ of its member libraries, in order to understand the implications for the community of a collectively-managed print resource in the future. It discusses the work of OCLC Research in using the OCLC WorldCat database for this analysis, taking account of inaccurate data matching and its effects, and considers how the RLUK analysis feeds in to broader work across the UK, led by Jisc, to create a UK National Bibliographic Knowledgebase. It compares the findings of the OCLC Research study to those of an earlier similar analysis of the collective Association of Research Libraries collection in North America. The governance and funding complexity of the UK is described to account for the challenges inherent in taking a national approach to the problems of managing a collective collection. The UK Research Reserve is described as an example of a shared print approach, thus far only applied to journals, which has over the last 10 years been a successful initiative for a number of participant libraries in allowing them to free up shelf space by removing duplicate holdings. The collective collection work of a subset of RLUK, the White Rose University Consortium in Yorkshire, is described as an exemplar of an implementation of the findings of the RLUK-wide study within a regional context.