Dataset developed from Alec Stone Sweet and Thomas Brunell's open-source database of preliminary reference cases at the Court of Justice of the European Union (‘The European Court and National Courts: Data Set on Preliminary References in EC Law, NEWGOV Project’ (2007) <http://www.eu-newgov.org/database/DELIV/DLTFIID04a-Data_Set_Preliminary_References_Art234_1961-2006.pdf).

The 'observations' file contains an entry for every preliminary reference case from 1961 to 2013. Each record contains: number of Member States at date of case; code of country from which preliminary reference originated; name of country; case number; case year; code(s) of detailed case topic(s) from most significant to a maximum of 5; general area(s) of case (e.g. agriculture, competition etc); institutions and Member States that submitted observations; for some date ranges the level of the national court referring the case; the number of citations of the case; whether a government department, public institution, lobbying group or only private individuals are parties.

The 'coding' file contains the subject codes (based on Stone Sweet and Brunell's codes but with codes added for some specific subjects, such as banking, gambling, public procurement) and the country codes.