A recent editorial in this journal stressed the need to rearticulate the methodology – and thereby the distinctiveness – of international law in the context of blurring disciplinary lines between international law and international relations. The aim of this article is to contribute to the methodological aspect of the debate. First, the article outlines a legal empirical approach, which complements legal methodology of international law with empirical tools and techniques such as citation network analysis and corpus linguistics. Second, the article applies the approach on the case law of two European courts: the Court of Justice of the European Union (CJEU), and the European Court of Human Rights (ECtHR). It demonstrates how the study of case citations and the language of courts enhance the validity, reliability, and transparency of the established legal method. In particular, scholars of international law gain a stable and complete quantitative basis for a further in-depth study of case law, precedent and interpretation. Additional benefit stems from a set of transparent criteria by which to criticize the jurisprudence of international courts. Firmer ground emerges from which to evaluate the courts’ role in the political process, their societal impact and their legitimacy. At the same time the approach preserves the main features of the distinct legal methodology of international law – especially its attention to legal detail.