Opening the black box of the Spanish legislative Process: The Legislative Amendments Dataset (1996-2023)

The Spanish Legislative Amendments Dataset provides comprehensive information on all amendments proposed to all executive bills introduced to the Spanish parliament from 1996 to 2023. At the bill level, the dataset provides information on the total number of proposed amendments to each bill (a total of 117.575), the parliamentary group proposing the amendments; and the main characteristics of each bill to which amendments were proposed. These characteristics include the bill title, date of proposal, the legislative committee that debated it, the bill topic, the type of law (if the bill is passed), the number of parliamentary appearances organized along the bill’s debate, and the bill’s regional and European content. This is the first systematic dataset of legislative amendments created in Spain. It is comprehensive (not sample-based) and was developed using web scraping and text-parsing techniques. The project was made possible through funding from the Spanish Ministry and the research projects OPPOL and LEGISPRO (RTI2018-096950-A-I00 and PID2021-127542NB-I00). The dataset is a valuable resource for researchers in political science, particularly those focusing on legislative studies, parliamentary behaviour, party dynamics, and political institutions. It is also relevant for teachers, interest groups, political parties, and other stakeholders (including public administrations and consulting firms) with an interest in, or affected by, legislation passed in the Spanish parliament.