What do Shepard's and KeyCite provide a list of?

Shepard's and KeyCite are both tools used in legal research to track the history and subsequent judicial treatment of legal cases. The primary function of these services is to provide a comprehensive list of prior cases that have cited a specific case. This allows legal practitioners to assess the authority and relevance of a case by revealing how it has been interpreted, followed, or distinguished in later decisions. Understanding the citation history can help in forming legal arguments and determining the case's status within the judicial system. By knowing which subsequent cases have relied on the original case, researchers can evaluate its standing and the weight it carries in legal precedents.

While there may be other features offered by these services, such as case summaries or annotations, the fundamental and most critical aspect they provide is indeed the list of prior cases that have cited the case in question.