Experts don’t agree – even when a loose standard of agreement is required (Chiang 2006)
SNOMED CT is very large and changes by 5-10% each release
Data is used in ways that might be unfamiliar to the originator
Reliability of SNOMED-CT Coding by Three Physicians using Two Terminology Browsers Michael F. Chiang, John C. Hwang, Alexander C. Yu, Daniel S. Casper, James J. Cimino, and Justin Starren AMIA Annu Symp Proc. 2006; 2006: 131–135.
Systems supporting coding may do better in avoiding “Paper trail” errors (O’Malley 2005)
O'Malley, K. J., Cook, K. F., Price, M. D., Wildes, K. R., Hurdle, J. F., & Ashton, C. M. (2005). Measuring diagnoses: ICD code accuracy.(International Classification of Diseases). Health Services Research, 40 (5), 1620(1620).
Patrick et al describe means of selecting the “most likely “ term or phrase.
Issues with identifying subsets and confirming correctness
J. Patrick, Y. Wang, and P. Budd, "An automated system for conversion of clinical notes into SNOMED clinical terminology," in Proceedings of the fifth Australasian symposium on ACSW frontiers - Volume 68 Ballarat, Australia: Australian Computer Society, Inc., 2007.
Although SNOMED CT is hierarchical, there are many relations in addition to IS-A subsumptions.
Any hierarchy is based on a particular view of the domain which may not match the reality
Concept Concept B Concept Concept Concept A Concept Concept Concept Concept Concept Concepts related to WHU Concepts Unrelated to WHU Concepts partially related to WHU Is-a Is-a Is-a Is-a Is-a To root concepts….
1 Membership value m 0 0 1 2 3 4 5 Value of “relatedness” response Not in subset Fully in subset Partially in subset
“ Growth measurements lie within normal limits for this gestation. Liquor volume is normal. Fetus is active. A single left fetal kidney is identified. No definite right kidney seen in the right renal fossa. Fetal bladder appears normal. “