Intermediate Representation Tutorial

The advantages of the OpenGALEN Intermediate Representation are:

1. (semi-)controlled vocabulary (Authoring Terminology), whose coverage is engineered to be just sufficient to support work in a particular subdomain.
2. multiple Authoring Terminologies specific to a subdomain.
3. independant of Target Terminology, ie Intermediate Representation expressions (dissections) can be transformed into concepts in any Target Terminology (e.g. into GALEN or SNOMED CT concepts).
4. a small number of concepts (called descriptors) - curated to be only the set of concepts actually used by a group of people working in a single circumscribed domain, at the very most 5000 relatively elementary terms.
5. simple syntax, no brackets, no keywords, easy to read.
6. a simple hierarchy of descriptors (for term finding only).
7. a small number of relationships (links) allowed between descriptors.
8. simple rules for when concepts may be linked (postcoordinated) with each other.
9. reductions in training time for authors.

As an example, here is the dissection for Gastroscopy:

RUBRIC "Gastroscopy"
MAIN inspecting
  BY_MEANS_OF endoscope
  ACTS_ON stomach

The advantages to the user of this approach are:

1. most of what you see is useful in your particular subdomain.
2. concepts and links are easy to find.
3. it is obvious how concepts might be combined.
4. your dissections can be transformed to different Target Terminologies.
5. better interfaces can be built to support the user.

The original reason for the development of the Intermediate Representation in the GALEN Programme is described here.