Beyond Partnership Quantity: A Meso-Level Framework for Effective External Cooperation in International Development Organisations

International development organisations have never maintained more formal cooperation agreements, yet the relationship between partnership quantity and development outcomes remains empirically inconclusive. This article argues that explaining this gap requires shifting the unit of analysis from the system level to the meso level: the interface between organisational headquarters and regional offices where cooperation is designed and governed. Drawing on international organisation theory, the aid effectiveness literature, and scholarship on IO field presence, it develops a six-dimensional diagnostic framework comprising two enabling conditions (policy-domain convergence and instrumental complementarity), two failure mechanisms (authority diffusion and institutional learning deficits), and two design solutions (formalised joint action frameworks and relational capital). The framework is operationalised through observable indicators and applied in a structured, focused comparison of ten peer-organisation arrangements maintained by an OECD regional centre in Asia, alongside contrast cases that never reach institutionalisation. Institutionalised arrangements combine strong enabling conditions with limited authority-diffusion frictions; many proposed collaborations dissolve at the formation stage because no organisation commits resources; and formalisation and relational capital can operate as partial substitutes once repeated interaction stabilises expectations. The article contributes a meso-level framework and practical structural-quality indicators for cooperation design.