When small structures are submitted for publication in IUCr journals, they are analysed as part of the peer review process by the software suite checkCIF. The goal of this analysis is to provide an objective assessment of the quality and reliability of the published structure, with reference both to the available experimental data and the level of consistency with known chemistry. For this to work well, validation protocols have to keep up with advances in structure determination methodologies. Consequently, it is important that CIF tools and definitions are both practical and extended and revised regularly. The purpose and output of validation also have to be understood easily by users, reviewers and journal editors, some of whom may not be expert crystallographers.