The 2030 Sustainable Development Goals are highly interdependent. Lasting progress towards these goals requires collaboration among actors operating in diverse sectors and thematic domains. Yet, multi-sectoral collaboration is complicated by a variety of factors that tend to incentivise siloed action organised around individual interventions and budgets. This paper presents an analytical framework based on the concept of “economies of scope” for assessing and enhancing the efficiency of development projects for which there is a joint production process. We focus on the use of fair cost sharing methods such as the Shapley Value to dis-incentivise actors operating in inefficient siloes.