What tool is used to determine whether a case has been reversed or modified?

The tool used to determine whether a case has been reversed or modified is Shepard's Citator. This resource provides a comprehensive way to track the history and treatment of legal cases. By using Shepard's Citator, legal professionals can see how a case has been cited in later decisions, which helps to identify whether the case has been affirmed, reversed, modified, or overruled. This is crucial in legal research, as it allows users to understand the current standing of a case and ensures they rely on authoritative and relevant legal precedents in their work.

While Westlaw and LexisNexis also offer extensive legal research capabilities, including case law searches and legal analyses, Shepard's Citator specifically focuses on the citation history and subsequent treatment of cases, making it the preferred tool for verifying changes in a case's status. A case brief, on the other hand, is typically a summary of a case's facts, issues, and rulings, and does not provide information about whether a case has been reversed or modified.