Assuming that we are limited to 89 atoms of the periodic table as is the case with the MP database, then the number of possible compositions that can be formed is 89 C 1 + 89 C 2 + 89 C 3 + 89 C 4 + … which is practically infinite. There are currently 20,855 materials in the MP with 3 elements, yet there are 89 C 3 ~70 billion possible compositions with 3 elements. Suppose we want to find the value of E h for a material with a composition made from 4 elements, C. MP will be lacking a large number of the possible compositions that are formed from subsets of C. Suppose that we calculate E h for C at this very moment, and let us label that value E h 2025 . If some of the possible compositions for the subsets of C were introduced to the MP in 2026, then the value of E h 2026 will be different from the value of E h 2025 . The value of E h might change either up or down subject to material discovery efforts. This means that a material might have a negligible value of E h 2025 , and hence believed to be stable, only to be deemed unstable when E h increases upon the discovery of new reaction products, becoming E h 2026 .