Thos Green, 'About my work' page 4:

Models of information artifacts: 2. OSM

Ontological Sketch Models

This is a new approach that I am working on with Ann Blandford. In brief: OSM looks for misfits between the user's conceptual model of a domian, and the conceptual model inherent in an interactive device. These misfits are a lightly formalised subset of the cognitive dimensions (see my other pages), giving an approach that is less broad-brush than cognitive dimensions yet not as over-detailed and intricate as, task-action grammar or many other HCI formalisms. Purely task-based approaches such as GOMS cannot spot the the same misfit problems because they do not take account of the conceptual models.

We are developing a methodology making use of a form-based 'OSM editor' to allow designers (non-specialists in HCI) to set up a model quickly and easily. An analysis program then scans the model and delivers 'usability alerts', warnings of potential troubles caused by misfits.

Publications and Reports

At present there is little written about this approach.

• A. Blandford and T. R. G. Green (1997) OSM: an ontology-based approach to usability evaluation. Workshop on Representations, Queen Mary College London, 1997. Click here for an RTF version.

  Abstract:
  An Ontological Sketch Model (OSM) is a structured but informal representation of the ontology &emdash; the essential underlying structure &emdash; of a system, forming a basis for usability assessment. Our primary aim is to develop an approach that is usable and that yields useful results.

  We present a preliminary ontology for the OSM, based on descriptions of the entities in the domain of application, actions that the user can perform, and relationships (such as "constrains" and "affects") between entities. Initial studies into the usefulness and usability of OSMs indicate that the approach is promising, but that further work is needed on developing more comprehensive training materials.

• A. Blandford and T. R. G. Green (1997) Design and redesign of a simultaneous representation of conceptual and device models. Submitted.

• T. R. G. Green and A. Blandford (1997) Ontology Sketching: catching usability problems by spotting misfits. Available in RTF or in HTML.

  Abstract:
  We introduce a new HCI modelling technique, 'Ontological Sketch Modelling', which identifies certain types of usability problem by exposing misfits between the user's conceptual model and the conceptual model imposed by the device. These types of problem are not addressed by previous techniques of HCI analysis. To make the approach widely accessible and easy to use we are developing an 'OSM editor'; after describing a device using the editor, the user can obtain a computer-generated analysis containing 'usability alerts', which warn of potential misfits.

Examples of small OSMs

See OSM examples