Background
Transitioning from an old medical coding system to a new one can be challenging, especially when the
two coding systems are significantly different. The US experienced such a transition in 2015.
Objective
This research aims to introduce entropic measures to help users prepare for the migration to a new
medical coding system by identifying and focusing preparation initiatives on clinical concepts with more
likelihood of adoption challenges.
Methods
Two entropic measures of coding complexity are introduced. The first measure is a function of the
variation in the alphabets of new codes. The second measure is based on the possible number of valid
representations of an old code.
Results
A demonstration of how to implement the proposed techniques is carried out using the 2015 mappings
between ICD-9-CM and ICD-10-CM/PCS. The significance of the resulting entropic measures is discussed in
the context of clinical concepts that were likely to pose challenges regarding documentation, coding errors,
and longitudinal data comparisons.
Conclusion
The proposed entropic techniques are suitable to assess the complexity between any two medical cod
ing systems where mappings or crosswalks exist. The more the entropy, the more likelihood of adoption
challenges. Users can utilize the suggested techniques as a guide to prioritize training efforts to improve doc
umentation and increase the chances of accurate coding, code validity, and longitudinal data comparisons.