In this article, we present attrition, a suite of commands to simplify the maintenance and documentation of implemented exclusion criteria and attrition conditions using standard Stata facilities and to generate an attrition diagram. attrition can be used, both from the command line and in do-files, to keep the diagram up to date with the analysis it documents. Six subcommands (set, exclude, count, tab, list, graph) allow the diagram to be constructed in a versatile way.