||This paper investigates interpretational ambiguity with reference to the ECC Treaty, and analyses its consequences. Theoretically, it suggests that incomplete contracts generate interpretational ambiguity, due to transaction costs but also to the inherent variability of language. Methodologically, the paper utilises an innovative automated text analysis approach to measure the specificity of Treaty provisions and their effects. Empirically, the analysis is based on a dataset that tracks the evolution of the entire body of EU-level secondary legislation and case law from 1957 to 2000. The paper finds a significant negative relationship between the indicators of article specificity and the number of laws and court rulings. This paper thus provides support for studies arguing that supranational actors including the Commission and Court of Justice will utilize ambiguity to further their institutional and political agendas.