In partnership with Southern Voice, this research project aimed to rebuild the discourse on development effectiveness from a Southern perspective by developing a new methodological framework. The key objective was to create a methodological guide that leverages innovative data sources and techniques. The study provided an overview of potential open-access and public data, referencing case studies relevant to development effectiveness assessment. It conducted a comparative review of the use of innovative data and techniques—including geospatial information and Big Data—in developing countries, highlighting their advantages, limitations, and associated challenges such as privacy issues. Ultimately, the study proposed alternative methodologies applicable at the country level for measuring development effectiveness, relating these methodologies to inputs, processes, and outputs.