CSO Sustainability index is a key analytical tool for measuring the progress of the civil sector in the region of Central and Eastern Europe and Eurasia. The index tracks the progress of the civil sector in twenty-nine countries over the past fifteen years.

The index takes into account the overall enabling environment for civil society, focusing on the legal environment for CSOs, organizational capacity, financial viability, advocacy, service delivery, infrastructure and public image.

Each dimension is assessed according to a scale of seven stages where the number 1 indicates a very advanced level, and the number 7 is very low level of development. The index was developed by the US Agency for International Development in collaboration with local organizations from countries where the index applies.