Legal citation indexes, known as citators, record and display information about the later-citing history and treatment of a dispositive legal document, usually a judicially published opinion, or "case." Presently, citators are digital tools integrated into large Web-based legal research platforms. This paper analyzes the accuracy with which descriptions of subsequent negative treatment are applied by a citator that employs a hierarchical controlled vocabulary-Shepard's Citations (a LexisNexis product)-as opposed to one that does not-KeyCite (a Thomson Reuters product). A framework for assessment is proposed and employed. The study's results suggest that a system making use of a hierarchical controlled vocabulary does apply descriptions of subsequent negative treatment in a marginally more accurate way. A discussion of the citator's place in legal research follows, including the suggestion that legal research instructors and researchers themselves, namely lawyers, should reconceptualize the role citators occupy in the research process.