In 2007 the International Association of Constitutional Law established an Interest Group on the Use of Foreign Precedents by Constitutional Judges to conduct a survey of the use of foreign precedents by Supreme and Constitutional Courts in deciding constitutional cases. Its purpose was to determine - through empirical analysis employing both quantitative and qualitative indicators - to what extent foreign case law is cited.
The study is thereby aimed at testing the reliability of studies describing and reporting instances of 'trans-judicial dialogue' between Courts. The research also provides useful insights into the extent to which a progressive constitutional convergence may be taking place between Common law and Civil law traditions.
The present work includes studies by scholars from African, American, Asian, European, Latin American and Oceania countries, representing jurisdictions belonging to both Common law and Civil law traditions, and countries employing both centralised and decentralised systems of judicial review.
The results, published here for the first time, give us the best evidence yet of the existence, and extent, of a transnational constitutional dialogue between courts.