Post-coordination Implementation Challenges Project IHTSDO Conference October 2010 Jay Kola

Outline Project Overview -- What we said we’ll do… Activity Report-- What we did… Problem Space-- What we understood… – User interfaces – Storage – Query Where to from here…

Why we might want to use Post- coordination Courtesy : David Markwell, CiC

Problem Space Overview User interface Storage ArchitectureQuery & Retrieval

Project Overview The project aims to identify challenges, solutions, and use cases relevant to the implementation of SNOMED CT enabled systems that support post-coordination. These challenges will be: Compiled into a list of curriculum topics, for guidance on creating post-coordination enabled systems. Used as a starting set of functional use cases, for development of a post-coordination tool kit. Used to identify a working boundary between pre and post-coordination in systems, as relevant to implementation.

Activity Report Webinars topics: – User interfaces Stan Huff David Markwell – Storage David Markwell – Query James Campbell Jay Kola

Problem Space - Revisited User interface Storage Query + retrieval Content Messaging

User Interface Overview User interface Chronic Asthma Asthma Chronic + + Valid use cases exist for both! Single-slot vs Multi-slot Approach Display + Rendering Fracture Femur Laterality : + Due to: Left Fall down stairs Fracture Femur+ Laterality : Left What if : Not all modules in SystemA can handle multi-slot approach? What if : SystemB receives a post-coordinated expression from SystemA, but can’t support post-coordination? Selection + Data entry

Webinar Report - 2 Issues with post-coordination enabled user interfaces – Users continue to request pre-coordinated terms; even when interface allows post-coordination. – Modifiers rarely used to generate post-coordinated expressions. – Need a sophisticated model to restrict creation of ‘non sense’ post-coordinated expressions. – Local data dictionary created – contains complex pre- coordinated terms mapped to post-coordinated expressions behind the scenes.

Webinar Report - 3 Post-coordinated expressions – user interface issues and options – Search: Options proposed Previously constructed expressions Detecting common refining value Concept model rationalised searched Constrained model rationalised searches – Rendering : Options proposed Display equivalent concepts (if present) Use proximal primitive + refinements Use of attribute-value pairs Heuristics for re-ordering qualifiers, removing duplication, flattening nested expressions – Data entry: Options proposed Sophisticated interfaces – structured data entry Auto encoding of text

Storage Architecture - 1 Asthma Course Severity Severe Acute Focus ConceptSeverityCourse AsthmaSevereAcute …..….

Storage Architecture - 2 Storage Architecture Query & Retrieval Single-slot vs Multi-slot Approach Multi-slot storage feels intuitive to system developers

Storage Architecture - 3 Storage Architecture Query & Retrieval Focus Concept 1 aa a bbb xxxx bbb yyyy Filler Concept 1 Single-slot vs Multi-slot Approach Nested normal forms are hard to represent in multi-slot approach

Storage Architecture - 4 Storage Architecture Query & Retrieval Single-slot vs Multi-slot Approach Does not feel intuitive to system developers; architectural issues

Webinar Report - 4 Supporting post-coordination with an expression repository – Table of unique post-coordinated expressions maintained locally. – Maintenance – automated process for storing and indexing post-coordinated expressions (+ ? Text rendering) – Facilitated by using UUIDs and Normal Forms – Optimisation strategies proposed – expression link tables, transitive closure table, etc

Query & Retrieval Storage ArchitectureQuery & Retrieval Single-slot vs Multi-slot Approach Multi-slot storage amenable to SQL like query languages ; optimised for performance Single-slot storage creates larger indices; needs other optimisation strategies ConceptClinical courseSeverity AsthmaChronic--- …..…. Expression Astham: clinical_course = Chronic ….. Chronic Asthma Predicated on the notion that Asthma Chronic + + = =

Where to from here… Common question: Does it actually work? If so, how does it work? – ?? Directions for solution space – User interfaces Heuristics? Research – Storage models Is it possible to optimise for multi-slot approach? Optimise for single-slot approach + ?DL reasoner – Query & Retrieval NHS UK work on SNOMED CT Reporting Project Further research with IHTSDO funding? – Content – Pre-coordination Roadmap project? Afternoon’s discussion

Discussion Implementation guidance – Better access – Possibly more intuitive ? Start with patterns Post-coordination advantages – Remember the benefits Interoperability – Messaging – ? Search Vendors – Local extensions? – guidance – Decouple core from extensions (with pre-coordinated terms)? Engineering issuee – Separation between readability and serialisation?