Fig. 4From: 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)The volume of procedures for three categories of retired codes (dotted lines) vs. current codes (solid lines of the same colors). This visualizes the rapid drop-off of retired codes in transition years (2005,2010,2012)Back to article page