Table 1 Algorithm to place retired codes into the 2014AA BioPortal CPT hierarchy using the property of numerical similarity. The algorithm first creates a list of all groupers (g) in the 2014AA Bioportal CPT ontology, their hierarchical level (l), and the minimum (a) and maximum (b) code under each grouper. Then, the the algorithm finds a grouper (g) where max(l)|a<d<b for each deprecated code d

From: A numerical similarity approach for using retired Current Procedural Terminology (CPT) codes for electronic phenotyping in the Scalable Collaborative Infrastructure for a Learning Health System (SCILHS)