The Nexus Project is a collaboration between IFPRI and its partners, including national statistical agencies and research institutions. Our aim is to improve the quality of social accounting matrices (SAMs) used for computable general equilibrium (CGE) modeling. The Nexus Project develops toolkits and establishes common data standards, procedures, and classification systems for constructing and updating national SAMs. This addresses the need for greater transparency and consistency in SAM construction to strengthen model-based research and policy analysis in developing countries. Nexus SAMs allow for more robust cross-country comparisons of national economic structure, especially agriculture-food systems. The Nexus Project’s guiding principles are that all data should be traceable to original sources and/or assumptions, and that all SAMs should be freely available online. Greater transparency and accessibility should facilitate more data validation and participation of the modeling community. Statistics are continuously being revised and errors are often only identified when data is used for analysis, and so we welcome your suggestions on how the SAMs can be improved to reflect new and/or better information.

The open access versions of Nexus SAMs separate domestic production into 42 activities. Factors are disaggregated into labor, agricultural land, and capital. Labor is further disaggregated across three education categories. The Nexus SAM defines household groups, namely rural and urban households disaggregated by per capita expenditure quintiles. The remaining accounts include enterprises, government, taxes, savings-and-investment, and the rest of the word.

Nexus SAMs are constructed using a Nexus SAM Building Toolkit developed by IFPRI. During the first stage, a Macro SAM is constructed from and fully consistent with official National Accounts, Government Finance Statistics, and Balance of Payments data. During the second stage, income and expenditure shares derived from household surveys and other sources are used to disaggregate the Macro SAM across multiple activities, commodities, factors, and households. Account imbalances are corrected through cross-entropy estimation.