Main Act or Side Show? Model Agreements by International Institutions and their Reuse in Investment Treaty Texts

Scholars and negotiators often assert that model treaty texts published by international organizations (IO) shape investment treaty design. This paper empirically investigates this role of IOs as shadow drafters. It tracks the imprint of six IO templates on the text of negotiated international investment agreements (IIAs) using the Electronic Database on Investment Treaties (EDIT). We find that the overall impact of IO models has been low. No IIA in our dataset copied from an IO model wholesale. Average annual similarity between model texts and negotiated IIAs is lower than 40% and significantly lower than the influence of IO models in the structurally similar international tax treaty regime. However, we do find evidence of an impact of IO language on specific salient clauses. For example, the text of key investment protection clauses in the 1967 Draft Convention of the Organization of Economic Cooperation and Development (OECD) was reproduced in hundreds subsequent IIAs and novel clauses on investor responsibility first introduced in the 2006 International Institute for Sustainable Development (IISD) model have subsequently been copied verbatim into negotiated IIAs. Our work concludes by discussing explanations for the comparatively low IO impact, notes other pathways for IOs to influence treaty design and sketches out an agenda for future research