Case Law Analysis — Judicial Decision Analysis

The ratio decidendi is the legal rule or principle that was necessary to decide the case — it is binding on lower courts under stare decisis. Obiter dicta are statements of law made in passing that were not essential to the outcome; they are persuasive but not binding. Misidentifying obiter as ratio overstates the authority of a proposition, which is a serious analytical error in both scholarship and practice.

With significant modification. Civil law systems (France, Germany, most of continental Europe, and Latin America) do not formally recognise binding precedent — courts are not obligated to follow prior decisions. However, judicial decisions do carry persuasive weight, and civil law scholars conduct 'jurisprudence analysis' of dominant court interpretations. The method must be adapted: the concept of ratio decidendi does not apply, and authority is assessed differently.

Completeness is approached rather than achieved absolutely. Best practice is to: (1) identify leading cases through multiple search strategies and secondary sources; (2) trace each leading case's citation history forward using a citator (e.g., KeyCite or Citator in legal databases); (3) check whether new searches yield cases not already in the corpus. When forward and backward citation tracing consistently returns cases already collected, saturation is reasonably established.

Legal content analysis systematically codes textual features of legal documents — often quantitatively — to answer empirical research questions about patterns across a large corpus (e.g., how often courts cite economic reasoning). Case law analysis focuses on the doctrinal meaning and precedential weight of individual decisions and their interrelations. The two methods are complementary: case law analysis identifies what the law is; legal content analysis studies patterns in how it is articulated or applied.

A solid understanding of the relevant legal system — particularly the court hierarchy, the doctrine of precedent, and the legal area under study — is essential. Non-lawyers conducting empirical legal research often collaborate with legal scholars to ensure correct identification of ratio, appropriate weighting of authorities, and accurate doctrinal framing. Without that expertise, systematic errors in extracting and interpreting the ratio decidendi are very likely.