The Stepper project has two main goals:

1. To develop a stepwise method for formalization (in this context, XML transformation) of text documents of clinical guidelines
2. To develop the Stepper tool, an XML editor enhanced with features to support the above method

Some guideline formalisation methods favour a one-step, top-down approach using a a pre-defined model and the involvement of a domain expert and knowledge engineer. This process that can suffer from a lack of transparency (as shown, for example, in the difficulty of tracing back the exact source of every piece of knowledge in a resulting guideline application. Stepper, on the other hand, has been designed as a document-centric tool which takes a guideline text as its starting point, and splits the fomalisation process into multiple user-definable steps, each of which corresponds to an interactive XML transformation. The result of each step is an increasingly formalized version of the source document.

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Stepper Screen - click for full size image

Stepper contains an embedded XSLT processor which carries out non-interactive transformation. Mark-up and interative transformation are carried out by by rules expressed in a new transformation language based on XML called XKBT (XML Knowledge Block Transformation).

The Stepper method and tool have been tested in the formalization of WHO/ISH (International Society of Hypertension) hypertension guidelines and in guidelines for breast cancer care. Evaluation has shown that using step-by-step approach makes it possible to transform medical guidelines into fragments of operational code (e.g. Java) or into an instance of medical ontology (such as Asbru). Rules for transforming guidelines into the Asbru language have been implemented.

Although Stepper has been designed to support a bottom-up, stepwise approach to guideline formalisation, the tool is not yet designed to support the development of a complete decision support application. A series of XML transformations cannot produce a standalone, exectuable application.

A main advantage of Stepper lies in the clarity of the step-by-step approach it fosters. All user activities (all single transformations) are documented in XML files so another user can easily review the whole transformation process. Stepper provides an interface showing the interconnection between the source text and the model.

The document-centric approach supported by the Stepper tool ensures that all additions of "external knowledge" (knowledge not contained in textual guidelines) are kept track of in the guideline model. The approach can also help highlight knowledge missing from a source guideline.