SIST EN ISO 12381:2019

Health informatics - Time standards for healthcare specific problems (ISO 12381:2019)

This document specifies a set of representational primitives and semantic relations needed for an unambiguous representation of explicit time-related expressions in health informatics. This document does not introduce or force a specific ontology of time, nor does it force the use of a fixed representation scheme for such an ontology. Rather this document provides a set of principles for syntactic and semantic representation that allow the comparability of specific ontologies on time, and the exchange of time-related information that is expressed explicitly.
This document applies to both the representation of actual phenomena occurring in the real world (e.g. registrations in medical records) and to the description of concepts (e.g. medical knowledge bases).
This document is applicable to
a)    developers of medical information systems where there might be a need for explicit time-related concepts for internal organization (e.g. temporal data bases, temporal reasoning systems),
b)    information modellers or knowledge engineers building models for the systems mentioned in a),
c)    experts involved in the development of semantic standards on precise subdomains in health care where time-related information needs to be covered, (e.g. in the study of pathochronology, i.e. the discipline dealing with the time course of specific diseases), and
d)    developers of interchange formats for messages in which time-related information is embedded.
This document is not intended to be used directly for
—          representing what is true in time,
—          reasoning about time, or
—          representation of metrological time.

Medizinische Informatik - Zeitnormen für spezifische Probleme im Gesundheitswesen (ISO 12381:2019)

Informatique de santé - Représentation du temps dans le domaine de la santé (ISO 12381:2019)

Le présent document définit un ensemble de primitives de représentation et de relations sémantiques nécessaires à la représentation univoque des expressions relatives au temps explicites en informatique de santé. Le présent document ne présente ni n'impose aucune ontologie spécifique du temps, et il n'impose pas non plus l'utilisation d'un système de représentation fixe pour ce type ontologie. En revanche, il fournit un ensemble de principes de représentation syntaxique et sémantique permettant de comparer des ontologies spécifiques du temps et d'échanger des informations relatives au temps exprimées de manière explicite.
Le présent document s'applique à la représentation de phénomènes réels survenant dans le monde réel (enregistrements dans des dossiers médicaux, par exemple) et à la description de concepts (bases de connaissances médicales, par exemple).
Le présent document est applicable:
a)    aux développeurs de systèmes d'informations médicales pour lesquels des concepts relatifs au temps explicites peuvent être nécessaires à l'organisation interne (bases de données temporelles ou systèmes de raisonnement temporel, par exemple);
b)    aux modélisateurs d'informations ou cogniticiens qui créent des modèles pour les systèmes mentionnés en a);
c)    aux experts impliqués dans l'élaboration de normes sémantiques concernant des sous-domaines précis de la santé dans lesquels les informations relatives au temps doivent être traitées (étude de la pathochronologie, c'est-à-dire la discipline traitant du déroulement de maladies spécifiques, par exemple);
d)    aux développeurs de formats d'échange pour les messages contenant des informations relatives au temps.
Le présent document n'a pas pour objet d'être utilisé directement pour:
—          représenter ce qui est vrai dans le temps;
—          développer un raisonnement concernant le temps; ou
—          représenter le temps métrologique.

Zdravstvena informatika - Časovni standardi za vprašanja, specifična za zdravstveno varstvo (ISO 12381:2019)

Ta dokument določa nabor nazornih primitivov in semantičnih odnosov, ki so potrebni za nedvoumno predstavitev izrecnih časovno pogojenih izrazov v zdravstveni informatiki. Ta dokument ne uvaja ali uveljavlja specifične ontologije časa in ne uveljavlja uporabe vnaprej določene sheme predstavitve za tovrstno ontologijo. Namesto tega ta dokument podaja sklop načel za skladenjsko in semantično predstavitev, ki omogoča primerljivost specifičnih ontologij časa in izmenjavo časovno pogojenih informacij, ki so izrecno izražene.
Ta dokument se uporablja za:
1) razvijalce medicinskih informacijskih sistemov, pri katerih je čutiti potrebo po izrecnih časovno pogojenih konceptih za notranjo organizacijo (npr. začasne zbirke podatkov, začasni sistemi sklepanja);
2) informacijske modelarje ali inženirje znanja, ki izdelujejo modele za sisteme, omenjene v točki (1);
3) strokovnjake, ki sodelujejo pri razvoju semantičnih standardov za natančna podpodročja v zdravstvu, pri katerih je potreben zajem časovno pogojenih informacij (npr. pri preučevanju patokronologije, tj. veda o časovnem poteku določenih bolezni);
4) razvijalce formatov za izmenjavo sporočil z vdelanimi časovno pogojenimi informacijami.
Ta dokument ni namenjen za neposredno uporabo, ki:
1) predstavlja, kaj velja v času;
2) sklepa o času;
3) predstavlja metrološki čas (ki je zajet v drugih standardih).

General Information

• Status: Published
• Public Enquiry End Date: 30-Jan-2018
• Publication Date: 07-Oct-2019
• ICS: 35.240.80 - IT applications in health care technology
• Technical Committee: ITC - Information technology
• Current Stage: 6060 - National Implementation/Publication (Adopted Project)
• Start Date: 03-Oct-2019
• Due Date: 08-Dec-2019
• Completion Date: 08-Oct-2019
• Ref Project: EN ISO 12381:2019 - Health informatics - Explicit time-related expressions for healthcare-specific problems (ISO 12381:2019)

Relations

• Replaces: SIST EN 12381:2005 - Health informatics - Time standards for healthcare specific problems
• Effective Date: 01-Nov-2019

Overview

EN ISO 12381:2019 - Health informatics: Explicit time-related expressions for healthcare-specific problems (ISO 12381:2019) defines a standardized, ontology-neutral way to represent explicit time-related expressions in health information. The standard provides representational primitives and semantic relations to ensure unambiguous encoding and exchange of temporal information in clinical records, knowledge bases and data interchange formats - without forcing a single time ontology or fixed representation scheme.

Key topics and technical requirements

• Representational primitives and semantic links: Defines core predicational components (e.g., has-occurrence, has-duration, has-rate, has-frequency) and rules for labeling temporal expressions so they can be compared and exchanged reliably.
• Temporal comparators and complex links: Specifies comparators and composition rules to relate events, episodes and reference situations (before/after chains, calendar anchors, reference-to-reference relations).
• Applicability to real-world data and concepts: Covers both recorded phenomena (medical record entries, observations) and conceptual descriptions (knowledge bases, clinical guidelines).
• Conformance characteristics: Introduces structured conformance dimensions (levels for semantic specification, embedding depth, deictic complexity and formal rigor - e.g., LSS, LRE, LDR, LDC, LQI) so implementers can state and verify capability profiles.
• Scope boundaries: Intentionally not a temporal logic engine - it does not mandate reasoning algorithms, define metrological (clock) time representation, or resolve implicit temporal meaning (e.g., unspecified durations like “childhood” must be made explicit by the provider).

Applications and who should use it

EN ISO 12381:2019 is practical for:

• Developers of medical information systems (temporal databases, EHR systems, temporal reasoning modules) seeking consistent time-expression exchange.
• Information modellers and knowledge engineers building clinical data models, terminologies or knowledge bases that include explicit temporal attributes.
• Standards authors and domain experts creating semantic standards for subdomains where time sequencing is crucial (e.g., disease pathochronology, treatment timelines).
• Message and interchange format designers embedding precise temporal information in HL7, FHIR extensions or other healthcare messaging standards.

Practical benefits include improved semantic interoperability, clearer audit trails in medical records, and more reliable temporal queries and analytics across systems.

Related standards

While EN ISO 12381:2019 focuses on explicit temporal expression representation, it is complementary to other health informatics standards (EHR messaging, terminology and data exchange standards). Implementers typically use it alongside messaging formats (e.g., FHIR/HL7), clinical terminologies and temporal reasoning tools to achieve end-to-end interoperability of time-related healthcare data.

Keywords: health informatics, ISO 12381:2019, time-related expressions, temporal representation, healthcare standards, semantic interoperability, temporal data, medical records.

Standards Content (Sample)

SLOVENSKI STANDARD
01-november-2019
Nadomešča:
SIST EN 12381:2005
Zdravstvena informatika - Časovni standardi za vprašanja, specifična za
zdravstveno varstvo (ISO 12381:2019)
Health informatics - Time standards for healthcare specific problems (ISO 12381:2019)
Medizinische Informatik - Zeitnormen für spezifische Probleme im Gesundheitswesen
(ISO 12381:2019)
Informatique de santé - Représentation du temps dans le domaine de la santé (ISO
12381:2019)
Ta slovenski standard je istoveten z: EN ISO 12381:2019
ICS:
35.240.80 Uporabniške rešitve IT v IT applications in health care
zdravstveni tehniki technology
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EN ISO 12381
EUROPEAN STANDARD
NORME EUROPÉENNE
September 2019
EUROPÄISCHE NORM
ICS 35.240.80 Supersedes EN 12381:2005
English Version
Health informatics - Explicit time-related expressions for
healthcare-specific problems (ISO 12381:2019)
Informatique de santé - Expressions relatives au temps Medizinische Informatik - Zeitnormen für spezifische
explicites utilisées dans le domaine de la santé (ISO Probleme im Gesundheitswesen (ISO 12381:2019)
12381:2019)
This European Standard was approved by CEN on 2 March 2018.

CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this
European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references
concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN
member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by
translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management
Centre has the same status as the official versions.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,
Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and
United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2019 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 12381:2019 E
worldwide for CEN national Members.

Contents Page
European foreword . 3

European foreword
This document (EN ISO 12381:2019) has been prepared by Technical Committee ISO/TC 215 "Health
informatics" in collaboration with Technical Committee CEN/TC 251 “Health informatics” the
secretariat of which is held by NEN.
This European Standard shall be given the status of a national standard, either by publication of an
identical text or by endorsement, at the latest by March 2020, and conflicting national standards shall
be withdrawn at the latest by March 2020.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN shall not be held responsible for identifying any or all such patent rights.
This document supersedes EN 12381:2005.
According to the CEN-CENELEC Internal Regulations, the national standards organizations of the
following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria,
Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland,
Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Republic of
North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the
United Kingdom.
Endorsement notice
The text of ISO 12381:2019 has been approved by CEN as EN ISO 12381:2019 without any modification.

INTERNATIONAL ISO
STANDARD 12381
First edition
2019-07
Health informatics — Explicit time-
related expressions for healthcare-
specific problems
Informatique de santé — Expressions relatives au temps explicites
utilisées dans le domaine de la santé
Reference number
ISO 12381:2019(E)
©
ISO 2019
ISO 12381:2019(E)
© ISO 2019
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting
on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address
below or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: [phone]
Fax: [phone]
Email: [e-mail]
Website: www.iso.org
Published in Switzerland
ii © ISO 2019 – All rights reserved

ISO 12381:2019(E)
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Explicit semantic labelling of predicational components . 5
4.1 General . 5
4.2 Labelling of temporal expressions . 5
4.3 Labelling of basic temporal links . 6
4.3.1 General. 6
4.3.2 has-occurrence . 6
4.3.3 has-rate . 6
4.3.4 has-frequency . 6
4.3.5 has-duration . 7
4.4 Labelling of complex temporal links . 7
4.5 Temporal comparators . 7
4.5.1 General. 7
4.5.2 Temporal comparators in combination with events . 8
4.5.3 Temporal comparators in combination with episodes . 9
5 Characteristics of conformance .14
5.1 Provisions for conformance specification .14
5.2 Basic guidelines .14
5.3 LSS: Level of semantic specification .15
5.3.1 LSS(0) .15
5.3.2 LSS(1) .15
5.3.3 LSS(2) .15
5.3.4 LSS(3) .15
5.4 LRE: level of recursive embedding of time-related information .16
5.4.1 LRE(0) .16
5.4.2 LRE(1) .16
5.4.3 LRE(2) .16
5.5 LDR: level of deictic referential complexity .16
5.5.1 LDR(0) .16
5.5.2 LDR(1) .16
5.6 LDC: level of relative deictic referential complexity .16
5.6.1 LDC(0) .16
5.6.2 LDC(1) .16
5.6.3 LDC(2) .16
5.7 LQI: level of formal rigour of temporal expressions .16
5.7.1 LQI(0) .16
5.7.2 LQI(1) .16
5.7.3 LQI(2) .17
Annex A (informative) BNF description of the syntax used in the standard predications of
this document .18
Bibliography .19
ISO 12381:2019(E)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out
through ISO technical committees. Each member body interested in a subject for which a technical
committee has been established has the right to be represented on that committee. International
organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.
ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of
electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www .iso .org/directives).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www .iso .org/patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and
expressions related to conformity assessment, as well as information about ISO's adherence to the
World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT) see www .iso
.org/iso/foreword .html.
This document was prepared by Technical Committee ISO/TC 215, Health informatics.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www .iso .org/members .html.
iv © ISO 2019 – All rights reserved

ISO 12381:2019(E)
Introduction
Time is an important variable in healthcare, and standards are needed about how to represent
information with explicit references to time. This document is a first contribution to this harmonization
process, focusing on “representation” and “explicit reference”.
Indeed, a system for time-standards should have as a minimum requirement the capacity to order
temporal facts (situations, events, episodes) in three major ways, independent of any specific ontology
of time itself:
— by relating situations to a calendar;
— by relating situations to “reference” situations;
— by relating events together in “before- and after-” chains.
The main reason for this threefold organization is that our everyday temporal discourse contains
a variety of expressions that can only be regimented into a uniform style of analysis with a certain
artificiality.
The purpose of this document is to enhance, in a perspective of machine-machine and person-machine
communication, the generation of statements that are guaranteed to be understood unambiguously
with respect to the time-related expressions that are embedded within them.
The purpose of this document is not to develop a full-blown temporal logic, but a standardized way of
representing time-related expressions, such that all kinds of questions about the temporal organization
of situations can be answered on the basis of the information available. Nor is it the intention of the
framework presented here to provide a means to interpret the information in its original format.
Interpretation of the source information is the task of the provider of information itself. The framework
presented in this document allows information providers to express their time-related information in
such a way that the intended meaning can be unambiguously understood by a receiver.
This of course requires the use of a “restricted”, regimented model or language, allowing the
disambiguation of many time-related expressions uttered in natural language. The model (language)
presented in this document is restricted enough to allow such disambiguation for time-related
expressions in “traditional” medical language but is not expressive enough to account for all time
related linguistic phenomena that can be encountered in natural language.
This document provides representational tools for “explicit” time-related information. It does not allow
(nor encourage) the ad hoc interpretation of implicit temporal information. In an expression such as
“diabetes since childhood”, “since childhood” is an explicit temporal reference for the diabetes, but
the implicit information what “childhood” might mean (e.g. starting at the age of 2?), is not addressed.
However, the framework presented in this document has enough expressive power to allow a specific
provider of information to state explicitly what his or her understanding is of “childhood” is.
This document describes some conformance characteristics by means of which developers of health
care information systems can label specific modules of their systems as to the degree they are
compliant with the document. Although the framework itself does not deal with temporal reasoning,
the conformance characteristics can be used to evaluate to what level temporal reasoning is possible
with the information collected in a given system.
INTERNATIONAL STANDARD ISO 12381:2019(E)
Health informatics — Explicit time-related expressions for
healthcare-specific problems
1 Scope
This document specifies a set of representational primitives and semantic relations needed for an
unambiguous representation of explicit time-related expressions in health informatics. This document
does not introduce or force a specific ontology of time, nor does it force the use of a fixed representation
scheme for such an ontology. Rather this document provides a set of principles for syntactic and
semantic representation that allow the comparability of specific ontologies on time, and the exchange
of time-related information that is expressed explicitly.
This document applies to both the representation of actual phenomena occurring in the real world (e.g.
registrations in medical records) and to the description of concepts (e.g. medical knowledge bases).
This document is applicable to
a) developers of medical information systems where there might be a need for explicit time-related
concepts for internal organization (e.g. temporal data bases, temporal reasoning systems),
b) information modellers or knowledge engineers building models for the systems mentioned in a),
c) experts involved in the development of semantic standards on precise subdomains in health care
where time-related information needs to be covered, (e.g. in the study of pathochronology, i.e. the
discipline dealing with the time course of specific diseases), and
d) developers of interchange formats for messages in which time-related information is embedded.
This document is not intended to be used directly for
— representing what is true in time,
— reasoning about time, or
— representation of metrological time.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments) applies.
ISO 8601-1, Data elements and interchange formats — Information interchange — Representation of dates
and times — Part 1: Basic rules
ISO 8601-2, Data elements and interchange formats — Information interchange — Representation of
dates and times — Part 2: Extensions
ISO 80000-3, Quantities and units — Part 3: Space and time
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO 12381:2019(E)
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https: //www .iso .org/obp
— IEC Electropedia: available at http: //www .electropedia .org/
3.1
situation
phenomenon occurring (or having the potential to occur) at a particular time or over a particular time
period, in a given world context
Note 1 to entry: Situations cover phenomena which can occur in past, present or future time.
EXAMPLE "The patient suffered from pain which occurred over night", "pain occurring overnight."
3.2
property
attribute, quality, or characteristic of something
EXAMPLE "The temperature of a person."
3.3
time interval
portion of time of which the duration in a given context is considered to be significant and relevant
3.4
time point
portion of time of which the duration in a given context is considered to be insignificant or irrelevant
Note 1 to entry: This document does not specify any requirements on what entities should occupy time points,
and what entities should occupy time intervals, users are responsible for making such decisions (Clause 5).
Temporal references such as “Friday the 13th” can thus refer to a time point or a time interval, depending on the
context.
3.5
episode
situation (3.1) considered to occupy a time interval (3.3)
Note 1 to entry: Whether a situation is to be considered an episode or an event, is a decision taken by the provider
of the information, based on his or her perception of the phenomenon in a given context.
Note 2 to entry: It is possible to further subcategorize episodes into “states”, “culminations”, “processes”,
“actions”, or other conceptual entities that can be defined using additional conceptual aspects describing
particular properties of each of the various episodes. However, there is no need to do so within the scope of this
document.
EXAMPLE A patient’s stay in the hospital, the “episode of care” related to a medical problem.
3.6
event
situation (3.1) considered to occur at a time point (3.4)
3.7
predication
representation of a situation (3.1) in a language
EXAMPLE “The removal of Mr Jones’ appendix on 21 July 1994, at 9 o’clock in the morning.”
3.8
temporal reference
component of a predication (3.7) representing information related to time
2 © ISO 2019 – All rights reserved

ISO 12381:2019(E)
3.9
propositional clause
component of a predication (3.7) to which temporal references (3.8) refer implicitly or explicitly
EXAMPLE In the expression “taking syrup three times a day for 2 weeks”, the propositional clause is “taking
syrup”. To it are attached the temporal references “three times a day” and “for 2 weeks”.
Note 1 to entry: The term propositional clause is used here in a broader sense than in formal logic where a
proposition denotes a statement on what is true in a given world. In the context of this document, propositional
clauses do not impose a truth-value on the phenomena that are represented.
Note 2 to entry: This document allows for a recursive representation of information related to time (see Annex A
for a formal description). In expressions such as “severe headache lasting for half an hour after each meal”, both
“severe headache” and “severe headache lasting for half an hour” are propositional clauses, each at a different
level in the recursion. A propositional clause that is at the deepest level of recursion, i.e. to which no temporal
references are attached, is called propositional clause zero. In this example: “severe headache” is propositional
clause zero.
3.10
temporal link
component of a temporal reference (3.8) capturing the semantic relation in a predication (3.7) between
the propositional clause (3.9) and the temporal expression (3.13)
Note 1 to entry: In natural language, the temporal link can be grammaticalized with prepositions or other
constructs, such as in “on Monday”. Often, the link is not expressed explicitly, as in “tomorrow”. In formal
representations in conformity to this document, the temporal link shall be represented explicitly, or should be
unambiguously derivable from a data model.
3.11
basic temporal link
temporal link (3.10) specifying purely time-related information
EXAMPLE Has-occurrence, has-duration (see 4.4).
3.12
complex temporal link
temporal link (3.10) composed of a basic temporal link (3.11) and an embedded propositional clause (3.9)
Note 1 to entry: Complex temporal links can be used to express the contents of relational data bases according to
the provisions of this document.
EXAMPLE The predication “Severe headache this morning” can be analyzed into the propositional
clause “severe headache” and the temporal reference “this morning”. In a database management system, such
predications can be represented in a table with fields “ProblemId”, “Problem” and “TimeOfHappening”.
Time of happen-
Problem Id Problem
ing
I1 severe headache this morning
I2
ingestion of immediately
acetylsalicylic acid after I1
…
In this table, the contents of the “Problem” column refer to situations, and hence shall be considered propositional
clauses and the contents of the “Time of Happening” column are all temporal references.
Often, the time of recording of problems is also recorded as useful meta-information. According to the model
above, this should be done by adding two records in the table:
I3 recording of I1 1994-07-01:18:00:32
ISO 12381:2019(E)
I4 recording of I2 1994-07-01:18:00:35
In fact, this could be repeated for each record, even for the records in which the recording of the recording of
the . is recorded. Because only the recording time of a problem is of interest, and not the recording event itself,
the above scheme is simplified by adding an additional field, labelled “TimeOfRecording”, which is a complex
temporal link.
Problem Id Problem Time of happening Time Of Recording
I1 severe headache this morning 1994-07-01:18:00:32
I2 ingestion of immediately after I1 1994-07-01:18:00:35
acetylsalicylic acid
...
Other examples of complex temporal links are: StartDateOfSampleCollection (laboratory context), DateOfBirth
(administrative context), StartDateOfProblem, EndDateOfProblem (clinical history or diagnostic module of
electronic medical record systems), .
3.13
temporal expression
component of a temporal reference (3.8) specifying a time point (3.4), a time interval (3.3) or any allowed
combination of time points and time intervals.
Note 1 to entry: This document does not imply any restrictions on what combinations of time points and time
intervals are “allowed” as this depends entirely on the ontology of time defined in a particular context. However,
such an ontology can only be claimed to conform to this document when such combinations can be represented
by the temporal expressions described in this document.
3.14
absolute temporal expression
temporal expression (3.13) whose exact meaning in a given context can directly be derived from the
temporal expression itself
EXAMPLE “9’oclock”, “1994-04-12”, “Christmas”
Note 1 to entry: “exact meaning” refers here to the fact that absolute temporal expressions (by definition) contain
all the information required to relate the situation to a calendar.
3.15
relative temporal expression
temporal expression (3.13) whose exact meaning in a given context can only be derived from the
temporal references (3.8) of the predications (3.7) referred to in the temporal expression
EXAMPLE “headache starting after eating chocolate”. When the headache starts can only be known if it is
known when the eating of chocolate takes place.
Note 1 to entry: The “relativeness“ or “absoluteness” of a temporal expression does not imply any qualitative
preference. For pure temporal reasoning issues, absolute temporal expressions shall be preferred, but for medical
reasoning, this is not true. Reducing the two predications “eating chocolate at three o’clock” and “headache after
eating chocolate”, to “headache after three o’clock” would imply a dramatic loss of information from the clinical
point of view.
3.16
deictic temporal expression
temporal expression (3.13) whose exact meaning in a given context can only be derived from information
outside that context
EXAMPLE Expressions such as “now”, “yesterday”, “last Monday”, “in three weeks”, can only be given precise
meaning if the time of utterance is known.
4 © ISO 2019 – All rights reserved

ISO 12381:2019(E)
3.17
time interval expression
temporal expression (3.13) denoting a time interval (3.3)
3.18
duration expression
temporal expression (3.13) referring to the length of a time interval (3.3)
EXAMPLE “Three years”, “a long time”.
3.19
rate expression
temporal expression (3.13) denoting the change of a property (3.2) over a time interval (3.3)
Note 1 to entry: The change of the property is to be considered the situation on which information related to time
is given.
EXAMPLE “The patient’s temperature dropped 0,5 degrees Celsius per hour”.
3.20
frequency expression
temporal expression (3.13) denoting the number of repetitions of a phenomenon during a time interval (3.3)
Note 1 to entry: A frequency may be considered a special case of a rate (“number rate”).
Note 2 to entry: The time interval does not need to be represented explicitly as is the case in the examples below
of "often", "frequently" and "after each meal".
EXAMPLE “Twice a day”, “every 5 minutes”, “often”, “frequently”, “after each meal”, “never” “always”.
3.21
time series expression
temporal expression (3.13) denoting the occurrence of a situation (3.1) in a series of time point (3.4) or
time interval (3.3)
3.22
temporal comparator
specifier of the temporal relation expressed by the temporal link (3.10) between the propositional clause
(3.9) and a temporal expression (3.13)
EXAMPLE Temporal comparators that can be added to the temporal link has-occurrence are am
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