Empirical challenges in the study of employers’ organisations and their representativeness

This article examines the quality and relevance of the data available for measuring firms’ membership of employers’ organisations. The author notes significant discrepancies between the membership rates derived from the five different data sources available for France, which leads him, in particular, to rule out tax data. By focusing on survey data, the author shows that asking managers about membership of employers’ organisations in general, or about membership of a specific employers’ organisation from a list, can lead to significant differences in membership rates, which highlights the importance of how survey questions are worded. The author then proposes methods for estimating an aggregate membership rate at firm level based on surveys of workplaces with at least 11 employees.