This article explores the development of concepts related to the 'quality of employment' in the academic literature in terms of their definition, methodological progress and ongoing policy debates. Over time, these concepts have evolved from simple studies of job satisfaction towards more comprehensive measures of job and employment quality, including the International Labour Organization's concept of 'Decent Work' launched in 1999. This article compares the parallel development of quality of employment measures in the European Union with the ILO's Decent Work agenda and concludes that the former has advanced much further due to more consistent efforts to generate internationally comparable data on labour markets, which permit detailed measurements and international comparisons. In contrast, Decent Work remains a very broadly defined concept, which is impossible to measure across countries. We conclude by proposing three important differences between these two scenarios that have lead to such diverging paths: the lack of availability of internationally comparable data, the control over the research agenda by partisan social actors, and a prematurely mandated definition of Decent Work that is extremely vague and all-encompassing.