Comparison of MeSH automated (MAA) and manual indexing annotations with a series of algorithmic filters added. From left to right, filters are applied cumulatively. "False Positives" are matches found by the algorithm but not in manual indexing. "True Positives" are found by the algorithm and in manual indexing. "In text, not found" are found in manual indexing, but not by the algorithm. "Not in text" are manually indexed terms not found in the abstract.