Iso tc tc 215/sc n339 Date: August 2003 iso/pdts

3.11 atomic reference terminologies

a reference terminology that consists of only atomic concepts and their systematic definitions

NOTE In this type of reference terminology, no two or more concepts can be combined to create a composite expression that has the same meaning as any other single concept contained in the atomic reference terminology.

3.12 colloquial terminologies

the set of terms, which consist of commonly-used entry points, that map to one or more canonical terms within the vocabulary

3.13 compositionality

composite concepts are created from atomic and pre-coordinated concepts and must be able to be combined to create compositional expressions

EXAMPLE ‘Colon cancer’ comprises ‘malignant neoplasm’ and ‘large bowel’ as atomic components. In a compositional system, concept representations can be divided into atomic and composite concept representations. Composite concept representations can be further divided into ‘named pre-coordinated concept representations’ and ‘post-coordinated representation expressions. Within a composite concept, it may be possible to separate the constituents into three categories: ‘kernel concept’, ‘qualifier (also called ‘status’) concept’, and ‘modifier concept’.

NOTE A concept is a notion represented by language and identifies one idea. However, the term ‘concept’ in this Technical Specification is used to refer to the representation of a concept rather than the thought itself.

3.14 atomic concept

a representation of a concept that is not composed of other simpler concept representations within a particular terminology

NOTE In many cases atomic concepts will correspond to what philosophers call ‘natural kinds’. Such an entity cannot be meaningfully decomposed. Concepts should be separable into their constituent components, to the extent practical. These should form the root basis of all concepts.

EXAMPLE In SNOMED-CT®, ‘colon’ is a synonym for ‘large bowel’ and ‘cancer’ is a synonym for ‘neoplasm, malignant’. Therefore, the term ‘colon cancer’ is non-atomic as it can be broken down into ‘large bowel’ and ‘neoplasm, malignant’. Each of these two atomic terms has a separate and unique concept identifier, as does the pre-coordinated term ‘colon cancer’.

3.15 composite concept

a concept composed as an expression made up of atomic concepts linked by semantic relations (such as roles, attributes or links). [see notes in 3.10]

3.16 pre-coordinated concept

such an entity can be broken into parts without loss of meaning (can be meaningfully decomposed) when the atomic concepts are examined in aggregate. These are representations that are considered single concepts within the host vocabulary. Ideally, these concepts should have their equivalent composite concepts explicitly defined within the vocabulary

EXAMPLE The term ‘colon cancer’ is non-atomic; however, it has a single unique identifier, which means to SNOMED-CT® that it represents a ‘single’ concept. It has the same status in the vocabulary as the site ‘large bowel’ and the diagnosis ‘neoplasm, malignant’.

3.17 post-coordinated concept

a composite concept is not pre-coordinated and, therefore, must be represented as an expression of multiple concepts using the representation language. The system attempts to construct a set of concepts from within a controlled vocabulary to more completely represent a user’s query

EXAMPLE The concept ‘bacterial effusion, left knee’ is not a unique term within the SNOMED-CT® terminology. It represents a clinical concept that a patient has an infected left knee joint. This example cannot be represented by a single concept identifier; consequently a system must build a representation from multiple concept identifiers to fully capture the intended meaning of this case or lose information to free text.

3.18 types of atomic and pre-coordinated concepts

unique concept representations can be classified within a vocabulary into at least three distinct types: kernel concepts, modifiers, and qualifiers that contain status concepts. This separation allows user interfaces to provide more readable and, therefore, more useful presentations of composite concepts

3.18.1 kernel concept

an atomic or pre-coordinated concept that represents one of the one or more main concepts within a pre-coordinated or post-coordinated composition

3.18.2 modifiers and qualifiers - terms which refine the meaning of a kernel concept

constituents of a composite concept that refine the meaning of a kernel concept are known as modifiers or qualifiers

EXAMPLE1 ‘Stage 1a’ in the expression ‘having colon cancer stage 1a’ or ‘brittle, poorly controlled’ in the expression ‘brittle, poorly controlled diabetes mellitus’ are examples of qualifiers and modifiers. In general, these concepts are expressed as a link plus a value (‘attribute-value-pair’). Terminologies must support a logical structure that can support temporal duration and trend. Attributes must be themselves elements of a terminology, and fit into a practical model that extends a terminology.

EXAMPLE2 Two Cancers may be further defined by their stage and histology, have been symptomatic for a specifiable time, and may progress over a given interval. Attributes are required to capture important data features for structured data entry and pertinent to secondary data uses such as aggregation and retrieval. Kernel concepts can be refined in many ways including a clinical sense, a temporal sense and by status terms, such as ‘recurrent’.

3.19 Normalization of content

the process of supporting and mapping alternative words and shorthand terms for composite concepts

NOTE All pre-coordinated concepts must be mapped to or logically recognizable by all possible equivalent post-coordinated concepts. There should be mechanisms for identifying this synonymy for user created (new) post-coordinated concepts as well (i.e. when there is no pre-coordinated concept for this notion in the vocabulary). This functionality is critical to define explicitly equivalent meaning, and to accommodate personal, regional, and discipline specific preferences. Additionally, the incorporation of terms as synonyms, represented in a language other than that primarily used in the host vocabulary, can achieve a simple form of multilingual support.

3.20 normalization of semantics

in compositional systems, there exists the possibility of representing the same concept with multiple potential sets of atoms, which may be linked by different semantic links. In this case the vocabulary needs to be able to recognize this redundancy / synonymy (depending on your perspective). The extent to which normalization can be performed formally by the system should be clearly indicated

EXAMPLE The concept represented by the term “Laparoscopic Cholecystectomy” might be represented in the following two dissections:

Surgical Procedure: Excision”{Has Site Gallbladder}, {Has Method Endoscopic}

and

Surgical Procedure: Excision”{Has Site Gallbladder}, {Using Device Endoscope}.

3.21 multiple hierarchies

concepts should be accessible through all reasonable hierarchical paths, ie they must allow multiple semantic parents. A balance between number of parents (as siblings) and number of children in a hierarchy should be maintained. This feature assumes obvious advantages for natural navigation of terms (for retrieval and analysis), as a concept of interest can be found by following intuitive paths, ie users should not have to guess where a particular concept was instantiated

EXAMPLE One example of multiple semantic parentage is ‘stomach cancer’ which can be viewed as a ‘neoplasm’ or as a ‘gastrointestinal disease’.

3.22 consistency of view

a concept in multiple hierarchies must be the same concept in each case. The example of stomach cancer (see Clause 3.21) must not have changes in nuance or structure when arrived at via the cancer hierarchy as opposed to the gastrointestinal disease hierarchy. Inconsistent views could have catastrophic consequences for retrieval and decision support, by inadvertently introducing variations in meaning that may be unrecognised and therefore be misleading to users of the system

3.23 explicit uncertainty

notions of ‘probable’, ‘suspected’, ‘history of’ or differential possibilities such as a differential diagnosis list, must be supported. The impact of ‘certain’ versus ‘very uncertain’ information has obvious impact on decision support and other secondary data uses. Similarly, in the case of incomplete syndromes, clinicians should be able to record the partial criteria consistent with the patient’s presentation. This criterion is listed separately as many current terminological systems fail to address this adequately.

3.24 representational form

the representational form of the identifiers within the terminology should be meaningless. Computer coding of concept identifiers must not place arbitrary restrictions on the terminology, such as numbers of digits, attributes, or composite elements. To do so subverts meaning and content of a terminology to the limitations of format, which in turn, often results in the assignment of concepts to the wrong location because it might no longer ‘fit’ where it belongs in a hierarchy. These reorganizations confuse people and machines alike, as intelligent navigation agents are led astray for arbitrary reasons. The long, sequential, alphanumeric tags used as concept identifiers in the UMLS project of the National Library of Medicine exemplify well this principle.

4 Health indicators conceptual framework with associated attributes

4.1 Framework

The health indicator conceptual framework shall be as outlined in Tables 1 through 4. Equity spans across all dimensions of the framework, and can apply to any of the concepts or indicators contained therein.

Table 1 – Health indicators conceptual framework: Health status dimension

Sub-Dimension	Well-being	Health conditions	Human function	Deaths
Concept	HI00000001	HI00000002	HI00000003	HI00000004
Attributes	• Significant others • Nutrition • Economics • Satisfaction • Comfort • Happiness • Self-Esteem	• Diagnosis • Manifestations • Site • Etiology	• Disability • Impairment • Functional status • Related diagnosis	• Immediate cause • Acute conditions • Chronic conditions • Age • Sex • Expected life span

Table 2 – Health indicators conceptual framework: Non-medical determinants of health dimension

Sub-Dimension	Health behaviors	Social and community factors	Environmental factors	Genetic factors	Socio-economic factors
Concept	HI00000005	HI00000006	HI00000007	HI00000008	HI00000009
Attributes	• BMI • Tobacco use • EtOH use • Seat belts • Caffeine use • Exercise • Firearm safety • Fire safety	• Emphasis on healthcare • Emphasis on disease prevention • Social support for the patient • School readiness • Cost of housing • Literacy written • Literacy spoken	• Water purity • Distance to a healthcare facility • Handling of sewage • Fuels • Regulations regarding the environment	• Genetic fingerprint • Proteomic fingerprint • Post-transcriptional Modification of proteins • Phenotypic groupings • Rates of inheritable disorders • Associated disorder	• Economic status • Employment status • Employment availability • Education level • Education utilization • Social class • Profession • Net worth

WORKING DRAFT ISO/PDTR


Table 3 – Health indicators conceptual framework: Health system performance dimension

Sub-Dimension	Acceptability	Appropriateness	Competence	Continuity	Efficiency	Safety	Effectiveness	Security	Communication	Accessibility
Concept	HI00000010	HI00000011	HI00000012	HI00000013	HI00000014	HI00000015	HI00000016	HI00000017	HI00000018	HI00000019
Attributes	• Satisfaction scale • Value	• Practice • Measure • Value	• Practice • Measure • Value	• Practice type • Measure • Context • Value	• Practice • Measure • Value • Cost	• Practice • Condition • Harm • Risk of Harm • Level of Harm	• Recurrence • Survival rate • Admission rate	• Confidentiality • Authentication • Authorization • Non­repudiation	• Timely • Accurate • Sufficient • Pertinent • Interpretable	• Diagnosis • Age • Race • Sex • Culture • Religion • Country of origin • Location • Economic factors • Insurance

© ISO 2003 – All rights reserved 8

Table 4 – Health indicators conceptual framework: Community and health system characteristics dimension

Sub-Dimension	Resources	Population	Health system
Concept	HI00000020	HI00000021	HI00000022
Attributes	• Type • Level of funding • Source of funding • Level of expenditure on training • Level of expenditure on research • Number of units	• Density of physicians • Speciality • Location • Average salary • Salary range (95% confidence	• Type of utilization of services • Level of utilization of services • Type of accreditation • Level of accreditation
	• Cost per unit	interval) • Cost of care	• Duration of accreditation
			• Stability of health care services

5 Health Status

5.1 Health status dimension description

The dimension of health status is described in Table 5.

Table 5 — Health status dimension description

Sub-Dimension	Description	Examples of indicators
Well-being	Broad measures of the physical, mental and social well-being of individuals	• Self-rated health • Self-esteem
Health conditions	Alterations or attributes of the health status of an individual which may lead to distress, interference with daily activities, or contact with health services; it may be a disease (acute or chronic), disorder, injury or trauma, or reflect other health-related states such as pregnancy, aging, stress, congenital anomaly, or genetic predisposition (WHO)1	• Arthritis • Diabetes • Chronic pain • Depression • Food and waterborne diseases • Injury hospitalization
Human function	Levels of human function are associated with the consequences of disease, disorder, injury and other health conditions. They include body function/structure (impairments), activities (activity limitations, and participation (restrictions in participation). (WHO)2	• Functional health • Disability days • Activity limitation • Health expectancy • Disability free life expectancy
Deaths	A range of age-specific and condition specific mortality rates, as well as derived indicators.	• Infant mortality • Life expectancy
		• Potential years of life lost
		• Circulatory deaths
		• Unintentional injury deaths
NOTE 1 World Health Organization (2000)
NOTE 2 World Health Organization (2001)