An ontological approach to modelling tasks and goals.

Current approaches to modelling plans and processes in AI are limited by current understanding of "goals" and "intentions". We discuss this question in a medical context, viewing goals as clinical objectives and plans and processes as collections of tasks to achieve those objectives. The specific context for this discussion is the CREDO project, which aims to develop a comprehensive approach to supporting complex treatment plans and care pathways and provides an opportunity to carry out an extensive investigation of the key problem of formalising goals in medical informatics and AI generally. A review of 222 clinical services required in the management of breast cancer has yielded a systematic classification of tasks involved in breast cancer care and a similar classification of the clinical goals associated with these tasks. A six-component model of goal structure is proposed based on these ontological analyses. Although the model has been derived from a corpus of examples from medicine many of the issues encountered, and the solution proposed, appear to be relevant to other domains.

Modelling clinical goals: a corpus of examples and a tentative ontology.

Knowledge of clinical goals and the means to achieve them are either not represented in most current guideline representation systems or are encoded procedurally (e.g. as clinical algorithms, condition-action rules). There would be a number of major benefits if guideline enactment systems could reason explicitly about clinical objectives (e.g. whether a goal has been successfully achieved or not, whether it is consistent with prevailing conditions, or how the system should adapt to circumstances where a recommended action has failed to achieve the intended result). Our own guideline specification language, PROforma, includes a simple goal construct to address this need, but the interpretation is unsatisfactory in current enactment engines, and goals have yet to be included in the language semantics. This paper discusses some of the challenges involved in developing an explicit, declarative formalism for goals. As part of this, we report on a study we have undertaken which has identified over 200 goals in the routine management of breast cancer, and outline a tentative formal structure for this corpus.