Negation Sources

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• Werner Ceusters, Peter Elkin and Barry Smith, “Negative Findings in Electronic Health Records and Biomedical Ontologies: A Realist Approach”, International Journal of Medical Informatics 2007; 76: 326-333. PMC2211452.
  • "We introduced a new family of ‘lacks’ relations into the OBO Relation Ontology. . . . By expanding the OBO Relation Ontology, we were able to accommodate nearly all occurrences of negative findings in the sample studied."
• Werner Ceusters, Peter Elkin and Barry Smith “Referent Tracking: The Problem of Negative Findings” (MIE 2006), Studies in Health Technology and Informatics, vol. 124, 741–6. (This issue also published as Ubiquity: Technologies for Better Health in Aging Societies. Proceedings of MIE2006, edited by Arie Hasman, Reinhold Haux, Johan van der Lei, Etienne De Clercq, Francis Roger-France, Amsterdam: IOS Press, 2006.)
  • "Referent tracking" assigns IDs to things to avoid confusion, e.g., when two people assert that a patient has a fracture and it cannot be determied whether they are the same fracture. To the extent that particulars have identifiers, this is in line with Restful (or OWLish) URIs. But they are also required to be unique. Another constraint is the identifiers are only given "real world phenomena," so the question is how to handle something negated. The authors propose a new "lacks" relationship for describing particulars that don't exhibit identified universals.
• Alan Rector, What's in a Code?
  • On separation of ontology from terminology & use of "situation" construct to harmonize positive & negative assertions
• Alan Rector, Negation & Null Values (rough notes)
  • On preference for "absent" to "negation," at least at first
• SNOMED CT Technical Implementation Guide: see 7.8.2.4.7 Retrieving absent findings
  • This section discusses how negation changes the rules for subsumption testing. The solution is to reverse the candidate/predicate relation for Situation with Explicit Context findings using "known absent" or a descendant.
  • Note that this approach assumes a pattern of Procedure with explicit context. The pattern of an Observable with value "absent" is not addressed.
  • This approach can probably be generalized.
• Edward Cheatham, SNOMED CT Post-Coordination rules, Draft guidance document. NHS NPFIT, document NPFIT-FNT-TO-DPM-0311.01
  • Guidance suggests storing "close-to-user" forms is a more conservative approach, deriving canonical forms for data operations.