Data standards should play an important role in achieving inter-organizational interoperability. Millions are spent on development and adoption of these standards, but does it lead to interoperability? This important question is often not addressed. In this study data interoperability in the Dutch temporary staffing industry is studied by focusing on the quality of the SETU standard and its implementations in practice. The Stichting Elektronische Transacties Uitzendbranche (foundation for electronic transactions in the staffing industry) or SETU, develops and maintains standards for exchange of electronic data in the staffing industry. Our results show that although the SETU standard is equipped for achieving interoperability, this in practice has not been achieved due to low quality implementations. We raise the question why these studies are not being performed on every standard. Another result is that localizations (profiles) may be needed for