All development is ultimately about change, and this requires communication interventions. Communication must be framed in an integral "two-way" process that involves stakeholders, accounts for their perspectives, and understands their socio-political context. This two-way process constitutes a new communication approach, providing a better understanding of the development context, tailoring development initiatives during design and implementation, and contributing to more sustainable results. This paper presents the methodology used by the Development Communication Division (DevComm) fo the World Bank's External Affairs Vice-Presidency and its clients to improve development outcomes based on a Communication-based Assessment (CBA) approach.