The temporal dimension of the credibility of EU conditionality and candidate states’ compliance with the <i>acquis communautaire</i>, 1998–2009

<jats:p> Existing research seems to agree that European Union (EU) accession conditionality facilitated processes of political and economic transformation for the recent enlargement rounds. However, despite its importance, systematic research beyond small- N qualitative studies that produces generalizable insights is scarce. Most strikingly, it remains unclear at which stage of the enlargement process and to what extent candidate countries complied with EU law in the context of accession conditionality. Building upon previous theoretical accounts, the authors argue that candidates’ compliance behaviour can be examined more thoroughly when focusing on the credibility of EU conditionality at different phases over the process of accession negotiations, which are characterized by varying degrees of membership probability. The article’s main contribution stems from the empirical analysis, which employs generalized additive models on new data of candidate countries’ compliance with EU law under accession conditionality from 1998 to 2009. </jats:p>