1. December 2010. Cleft-Net-East Network, box 46, Addenbrookes Hospital
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The Cleft Project: the partition of information in a
Reference Model and a knowledge model
This essay will discuss two different modelling approaches with respect to building information
systems software according to underlying design models architecture, ability to communicate
to other systems as well as capacity of adaptation. It will focus on the so-called two-level
model methodology , whereby a higher level of abstraction is considered when it comes to
effectively serializing information about any domain, by means of complete separation of
domain information (actual knowledge) on the one hand, and metadata (information about
the underlying structural representation of the actual knowledge on any domain), on the
other hand.
First and foremost, let us recall the primary purpose of an information system is “to create
and process instances of business entities or concrete day-to-day entities” [3]. Historically,
for the accomplishment of such purpose, software designers have had to acquire the
necessary insights from the knowledge domain in question, so as to being able to hard-code
the domain concepts into the program logic models, thus using knowledge concepts in
attributes of classes and database schemas’ tables and columns. It was the so-called single-
level methodology approach (the classical way). With this methodology, if the system’s
requirements change or, even worse, if they have not been properly coded into the software
logic, there is always a cost in time and money to re-design and, ultimately, re-compile the
source code. In a health domain, the knowledge is constantly evolving and if the system
cannot keep up with the new requirements, it will eventually become obsolete and its utility
will diminish over time.
Another intrinsic problem of this approach is the imposibility of representing the relationships
between the different concepts within an ontology (“an explicit formal specification of the
terms in the domain and relations among them” [5]), but rather facts about the real world.
With this approach, “the software correctness and informational validity are directly
dependent on the definitions of knowledge entities from which the system is constructed” [3].
It is usually inherent to this classical methodology approach a truly vendor dependency,
particularly in proprietry software.
On the contrary, there is an emerging approach named openEHR two-level architecture,
whereby the model separates the semantics of information (Information level or metadata)
from the Knowledge concepts or knowledge level. This approach follows the principles of
RM/ODP methodology [25], which stands for Reference Model/Open Distributed Processing.

2. December 2010. Cleft-Net-East Network, box 46, Addenbrookes Hospital
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With so many different implementation technologies and closed standards and communication
protocols out there, there came a point in which the firms realized that trying to individually
reinvent the wheel was not a satisfactory solution. “It was more sensible to jointly work with
other companies towards common solutions that may help each individual enterprise reach
their goals, while sharing the problems, the costs, and the efforts” [25]. The solution was to
reach interoperability and the definition of stable frameworks or reference models [24] that
remain valid over time, for which common agreements on how to do things had to be met. As
stated by the Open Group [24], a reference model “consists of a minimal set of unifying
concepts, axioms, and relationships within a particular problem domain, and is independent of
specific standards, technologies, implementations, or other concrete details”. The openness of
Reference Model/Open Distributed Processing (RM/ODP) lies in the usage of common
frameworks and interfaces for all sytems conforming the abstract model.
The need for interoperability addressed the necessity of internationally agreed standards and
protocols, developed by Standards Developing Organizations (SDOs), with which to define a
lingua franca for information systems to be able to interoperate amongst themselves, with
disregard to technologies, programming languages, platforms and operating systems
deployed in each case.
Following on openEHR approach, this RM/ODP methodology implies the so-called separation of
responsibilities, whereby the different qualitative domains of business processes are divided
into managable parts implemented as standalone systems or services [7]. Additionally, from
the separation of responsibilities follows the RM/ODP separation of viewpoints, of which the
first two, namely informational viewpoint and computational viewpoint, correspond
respectively to the semantics of information (Reference Model or RM), on the one hand, and
the division of the system into interacting objects (the Service Model or SM), on the other,
both of which are part and parcel of the openEHR methodology.
From the point of view of the abstract specifications of the openEHR Specification Project
[18], aside from RM and SM, there is a third formalism named Archetype Model (AM).
Archetypes are structured models of domain content (i.e. diagnostics of a new born baby with
a cleft lip and/or palate), whose purpose is to provide a reusable, interoperable way of
managing data, in such a way it conforms to the generic structures defined in the
corresponding reference model. The instantiation of these generic structures results in
concrete types which, in “classic” information models, are hard-coded in the software. The
breakdown of information systems in domain models (knowledge proper) and information
models (meta-information of the data architecture which will be ultimately used in any
information system), makes it possible for software designers, on the one hand, and domain
experts (clinicians), on the other, to focus their work on their respective areas of expertise:

3. December 2010. Cleft-Net-East Network, box 46, Addenbrookes Hospital
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• Reference Model (RM) ISO/ODP informational viewpoint (semantics of
information processed by the system)
• Service Model (SM) ISO/ODP computational viewpoint (division of the
system into interacting objects)
• Archetype Model (AM) bridge between information models and knowledge
resources.
As a result, ever-changing health domain knowledge do not require re-design and re-
compilation of software, as amendments and/or additions of knowledge concepts (archetypes)
are handled by such systems on a runtime basis, provided that their Archetype Definition
Language (ADL) specification conforms to the semantics of constraint of its underlying
Reference Model.
Taken from [18]. © Copyright openEHR Foundation 2001-2007. All rights reserved. www.openEHR.org
Taking into account qualitatively different types of “information”, we can divide it into three
different categories as shown below:
Ontologies of information: 3 categories, namely information models (IM=RM+SM), domain content
models (AM) and terminologies (or ontologies of reality).
Variable Domain content models (archetypes & templates, AM) Versus stable information models
( (RM & SM) = IM )
Archetypes & templates: Act as a well-defined semantic gateway to terminologies, classifications and
computerised clinical guidelines.
Ontologies of reality (descriptions and classifications of real phenomena): Classifications, process
descriptions, computerized clinical guidelines and descriptive terminologies.

4. December 2010. Cleft-Net-East Network, box 46, Addenbrookes Hospital
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Taken from [18]. © Copyright openEHR Foundation 2001-2007. All rights reserved. www.openEHR.org
As an open project and a new electronic health record and health data/information
management paradigm, openEHR is near to final adoption at European and International
levels by ISO/CEN Standard Developers Organizations [17]. Ocean Informatics Pty, co-
founder of the openEHR Foundation alongside the University College London, recently
undertook a new project with the NHS with which to test content modelling as a technique for
producing standardised structured clinical data specifications. “NHS Connecting for Health
(NHS CFH) has decided to continue to use the Ocean clinical modelling tools and openEHR
archetypes and templates to help specify the information required to support safe and high
quality health care across clinical systems in England” [4]. As of 2008, openEHR is the model
of choice in implementing EHR in England and the most actively developed model [26].
As a result of the deployment of this open standard specification, volatile (variable) health
domain concepts would not have to be hard-wired into the software and database schemas,
but runtime instantiated to the program logic of the reference model, allegedly the only part
of the healthcare ontologies to be implemented in software. The knowledge level (Archetype
Model or AM) and clinical models development are more to do with international efforts led by
clinicians to build archetypes for use in clinical systems. In addition, openEHR clinical models
are freely available and have proven to be a valuable resource for those building clinical
applications, as well as those concerned with data standardisation and reporting [15]. These
major effort to design clinical models for sharing across applications, providers and
geographical boundaries and the fact archetypes have been created by clinical domain experts
around the world, has addressed the need for a central resource (the so-called Clinical
Knowledge Manager or CKM), of which purpose is to coordinate the sharing of archetypes,
support clinical collaboration and agreements upon clinical models, as well as terminology

5. December 2010. Cleft-Net-East Network, box 46, Addenbrookes Hospital
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bindings with Description Logic (DL) knowledge representations languages such as SNOMED
CT [14] [19].
It is worth noting that the openEHR EHR is not limited to creating a “patient-centred,
longitudintal, shared care EHR”, as it can be used as a model for a Local Health Record (EPR)
[18], something that East-of-England Cleft-Net-East clinical managed network for cleft
patients could benefit from if applied to its in-house classic relational database. As the
prospects of adding extra functionality to it are rather grim from the single-level methodology
point of view, the aim of this project is to develop an EPR for the Cleft Team following the
principles of the two-level methodology approach. It is envisaged that it would allow for the
system to not only be scalable (able to be enlarged) and extensible (implemented taking into
consideration future growth), but ultimately interoperable with other NHS systems.
One could argue that there is no need to do so considering we are one department only and
therefore assert that the number, complexity and rate of definitional changes should then be
rather small, but we have to bear in mind that Cleft-Net-East Clinical Managed Network
encompasses a variety of health disciplines and specialists that have to be actively involved
during a 20-year care pathway.
The attractiveness of this project lies in the fact we could eventually audit-trail cleft patients’
care journey. Clinical data does not have to be a volatile piece of information that changes
over time without the possibility of recording past patients’ status. In order to get the most of
the data and to be able to identify trends on ever-changing patients’ diagnostic progress, the
EHR model allows traceability of past, present, future and concurrent events.
Last but not least, this project aims to provide standardization for clinical data coding and
provision of care plans guidance in regards to the patient flow, depending upon diagnosis
types and clinical audit trail, thus introducing standardization and accountability for the team
and for the patient.
Author:
Juan-José Blasco Ramos, Activity & Information Manager, Cleft-Net-East
(juanjose.blasco@addenbrookes.nhs.uk, juanjose.blascoramos@nhs.net)

6. December 2010. Cleft-Net-East Network, box 46, Addenbrookes Hospital
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