The EVI or Economic Vulnerability Index is a measure of structural vulnerability to economic and environmental shocks.  High vulnerability indicates major structural impediments to sustainable development.  Thus, a higher EVI represents a higher economic vulnerability.

Since 2015 the CDP uses absolute thresholds for the EVI to determine inclusion and graduation eligibility.  The inclusion threshold has been set at 36.  The graduation threshold has been set at 10 per cent below the inclusion threshold at 32.  The EVI is composed of eight indicators, grouped into various subindices.  Original values for each EVI indicator are converted into index numbers using a max-min procedure.

Source: https://www.un.org/development/desa/dpad/least-developed-country-category.html