The Ottawa Group’s Contributions to CPI Methodology

The statistical treatment of quality change in Consumer Price Indices (CPIs) has long posed conceptual and operational challenges for national statistical offices. Beyond formal harmonization efforts led by international organizations, the creation of the Ottawa Group (OG) in 1994 established an informal expert forum in which statisticians and economists could confront these challenges through a mixture of practical experimentation and theoretical discussion. This article reconstructs the institutional and political conditions that enabled the OG's emergence and examines how this space contributed to the evolution of CPI methodology, particularly the question of quality adjustment, over the period 1994–2024. Drawing on an original database of 488 OG contributions, we combine qualitative historical reconstruction with bibliometric, co-citation, and thematic analyses to map the epistemic configurations that structured OG debates. The results reveal the coexistence of two enduring methodological orientations, one grounded in index-number theory and the other in pragmatic statistical practice, alongside a progressive consolidation of collaborative networks within the Group. Taken together, these findings show how the OG served as both a laboratory for methodological innovation and a site where divergent conceptions of "quality" were negotiated, contributing to the broader history of quantification and international statistical harmonization.