To amend or not to amend: under what circumstances do Spanish legislators propose amendments to executive bills?

Based on a new comprehensive dataset containing information on 93,722 amendments, this article explores the circumstances under which Spanish legislators propose amendments to executive bills. Our results show that legislators respond to variations in both governmental factors and bargaining dynamics. In single-party minority governments, ad hoc legislature agreements translate into more amendments. However, legislators do not introduce significantly fewer amendments under absolute majority governments, when the chances of their proposals being accepted fall. After controlling for many confounders, the results show that amending activity reacts to attention allocation dynamics – mediatised bills receive more amendments – but not to variations in contextual factors – the number of amendments does not significantly increase when the economic situation deteriorates. Finally, bills associated with a greater number of committee appearances from interest groups, experts and public officials are more often the target of amendments, signalling that an informational logic is also at play.