Methodologyfor

Action Verbs / Operations

Tony Weida

June 10, 2014

Introduction

• Methodology can guide progress through established objectives without extraneous detours• Temptation to minimize rework by trying hard to preserve existing

hierarchies, along with existing names and text definitions• A thoughtful step back may yield more consistent, integrated results• No silver bullet*

* By analogy to Brooks, Frederick P. , Jr. (1987). "No Silver Bullet—Essence and Accidents of Software Engineering". Computer 20 (4): 10.

Perspective on Integrating Existing Ontologies*• “… there is the question of how and whether to use [all or part of]

ontologies that already exist. In general this is a very difficult problem.”• “Skuce’s main point is that in order to agree on ontologies that can be

shared among multiple user communities, much work must be done to achieve agreement. One way forward is to make explicit all assumptions underlying the ontology.”• “… when there are similar concepts defined in existing ontologies, it is

rarely clear how and whether such concepts can be adapted and reused”

*Or for our purposes, vocabularies. Source: [Uschold and Gruninger]

Phases

1. Prepare2. Scope3. Enumerate4. Group, filter and conceptualize5. Define and classify6. Review and improve7. Document, approve and use

1. Prepare• Up front investment pays off• But don’t get bogged down

Naming Our Subject

• Agree on one name• Action• Verb• Action Verb• Operation

• Suggest single word: Action (or Operation)

Goal: Harmonized HL7 Vocabulary

• Shared across CBCC, EHR, Security and other HL7 specifications• Maintained separately from any individual specification

Working Artifact

As discussed …• Excel spreadsheet• Posted on HL7 Wiki• Stored and versioned in GForge

Format for Entries

• Name• Text definition

• Genus and differentia• Template(s): [To enter data is] to capture data by …

• Structured representation• Parent(s)• Other properties, e.g., affected objects (input and/or output), preconditions, postconditions, …

• Example(s)• Notes (assumptions, justifications, clarifications, etc.)• Decision history• Legacy definitions

Understand Concepts and Terms

• Preview: concepts and terms will factor into methodology• A concept represents a unique idea• A term refers to a concept (in natural language)• Each concept• May have multiple synonymous terms• Should have single preferred term

Terminology Elements (SNOMED)

• Concepts represent unique ideas

• Codes uniquely identify concepts

• Terms refer to concepts

• Typically• Humans communicate concepts using terms• Computers communicate concepts using codes

• Concepts are language independent; terms are language dependent

Myocardial infarction (disorder)22298006

Myocardial disease (disorder)57809008

Heart disease (disorder)56265001

Myocardial finding (finding)251052000

Disorder of Myocardium

Disorder of heart muscle

Myocardial disease, NOS

Cardiac disorder

Cardiopathy

Disorder of heart

Heart disease, NOS

Morbis cordis

Myocardial observation

Myocardial infarction

MI

Cardiac infarction

Heart Attack

Ataque cardíaco

Some Preliminary Considerations

• Addressing privacy operations (along with data operations)?• Necessarily committed to any pre-existing names, definitions or

hierarchical arrangement?• Definitions re affected object types?• Display vs. in memory vs. persistent (database) objects• Change existing object vs. create new object?

• Example: encrypt, mask, …• On-demand vs. persistent results?• … Eliminate, tolerate or embrace ambiguities?

• Separation of concerns between EHR and Security?

Separation of Concerns

• To what extent are actions shared?

EHR Security

EHR Security

SecurityEHR

• Not about ownership

2. Scope• What problems are we solving?• What coverage and granularity are required?

Target Audience

• HIT standards community• EHR, Security, CBCC …

• Authors• Reviewers• Adopters

• Policy makers (jurisdiction; provider)?• System implementers?• System adopters?

Purpose in General

• Communication among people and organizations• Interoperability (shared resource or interlingua)• Systems engineering (specification, implementation, …)

Motivating Scenarios

• High Level• Examples• Specify EHRS functionality

• Conformance• Record life cycle events

• Specify security and privacy policies; consent directives• Interoperate between EHR and Security subsystems

Competency Questions

• Types of questions the ontology (vocabulary) must be able to answer• Generally, ontology should also be confined to answering them• Thus contents are necessary and sufficient• Benefits• Specify scope by providing inclusion / exclusion criteria• Help to justify work effort• Assist with evaluation

Example Competency Questions

• What types of action can …• … an EHRS perform (on behalf of a user)?• … be specified in a security policy?• … an EHRS request ask a security system to authorize or deny?

• Does a given type of action specialize another?• What types of object(s) are acted on by a given type of action?• [In Security and Privacy Ontology context] Is user U playing role R

authorized to perform action A on object O from location L at time T … ?• Note: Questions can be stratified, in the sense that responses to

questions can composed to answer other questions

3. Enumerate

• Gather candidate terms• Not yet focusing on concepts, definitions or hierarchy• Take existing lists• EHRS-FM Verbs• EHR-RMES Lifecycle events• Security and Privacy Ontology (SPO) operations

• Brainstorm any additional terms (nonjudgmental, for now)• Note: initial focus on terms defers differences in understanding of

fundamental concepts

4. Group, Filter and Conceptualizea. Identify work areasb. Assign terms to work areasc. Coalesce concepts from terms

4a. Identify Work Areas

• Choose “naturally arising sub-groups” [Uschold and King]• Items within a group are relatively similar semantically• Items in different groups are relatively dissimilar

• Not necessarily hierarchical classes• Might still start with top levels of EHRS-FM verb hierarchy

4b. Assign Terms to Work Areas

• For each term• Considering our focus, decide to include, discard, or note as borderline case• Assign to appropriate area

4c. Coalesce Concepts from Terms

For each work area• Identify concepts as collections of synonymous term(s)• Note near synonyms – with clear distinctions

5. Define and Classify• Text definitions must precisely reflect taxonomy and vice versa• Thus, effectively need to iterate an integrated process

Text Definitions [Uschold and Gruninger]• Ensure consistency with existing (previously defined) terms• Avoid introducing new terms where possible• Avoid circularity• Necessary and sufficient, as far as possible in natural language• Follow template(s)

Definitional Challenges [Uschold and King]When it’s hard to define or reach consensus about a term …• Clarify underlying concept (via research, discussion, etc.)• Temporarily use meaningless label to avoid getting hung up, and

define underlying idea• Attach a term accordingly (ideally not the original, problematic term)

Prefer Middle-out Approach [Uschold et al.]• Bottom-up: results in much detail, thus increasing overall effort,

obscuring commonality, and increasing risk of inconsistency, hence rework• Top-down: better control of detail, but may yield arbitrary high level

categories risk of less stability, thus rework• Middle-out:• First define “most fundamental” terms in each area• Strikes a balance; reduces potential for rework

5. Define and Classify

• Start with work areas having the most semantic overlap with other areas (get them right first, because mistakes lead to more re-work); If little overlap, proceed in any order [Uschold and Gruninger]• For each work group in turn …• For each concept

• Select name (i.e., designate the single preferred term)• Draft precise text definition, ensuring consistency with all previously defined terms• Separately

• Give examples as appropriate• Note assumptions, justifications and clarifications

• Place into taxonomy• Ensure that text definition reflects position and vice versa

6. Review and Improve

• Present to parent work groups for discussion and feedback• Solicit feedback from other experts?

7.Document, Approve and Use

1. Finalize taxonomy with concepts, terms, text definitions, etc.2. Prepare and submit harmonization proposal3. Adopt in new or revised HL7 specifications

Recap of Phases

1. Prepare2. Scope3. Enumerate4. Group, filter and conceptualize5. Define and classify6. Review and improve7. Document, approve and use

Discussion