The process of subject analysis and Library of Congress Subject Heading assignment is, despite the availability of rules and standards, a subjective one. Disagreements and inconsistencies between cataloguers regarding the correct Library of Congress Subject Headings for a given resource are widespread. This paper attempts to address the problem of these indexer inconsistencies by utilising the wisdom of the crowd. The various headings suggested by different cataloguers, for a particular resource from a large number of library catalogues, can be collated to create a coherent, valid, and consistent set of Library of Congress Subject Headings that represent the collective wisdom of the cataloguers.