Why does Anatomy Lens return more results than PubMed for certain MeSH queries?
MeSH is formally not a taxonomy, but it is organized as separate trees. For example, if you consider the trees for the term Program Evaluation in the MESH browser, you will notice that Program Evaluation appears in three trees, and only in two trees does it contain the subclass Benchmarking. To be consistent in our expansion of MeSH concepts, we treat these separate trees as a directed acyclic graph and assume that Program Evaluation always needs to be expanded to Benchmarking.
