FACTORS PROMOTING REVISION

A number of factors have contributed to a need for an update of GEM:

(1) A need for additional concepts to describe guideline documents

GEM's purpose is to model comprehensively the guideline document. Several stakeholders have determined that additional concepts would be valuable to describe document components and to begin the process of transformation of guideline knowledge into a decision support tool. For example, at the Conference on Guideline Standardization, guideline developers, disseminators, and implementers created a checklist of necessary guideline content that called for inclusion of several concepts not previously represented in GEM, including: role of sponsor (sponsor's part in developing, modifying, and reporting the guideline); conflict of interest (potential situations in which financial or other considerations may compromise, or have the appearance of compromising, a developer's professional judgment); evidence selection criterion (method used to choose the studies that inform guideline development, including inclusion and exclusion criteria); and research agenda (a proposal for further scientific investigation to correct identified deficiencies in the evidence base for this guideline topic). GEM users and researchers have suggested a number of additional terms to meet specific needs: e.g., goal (the state that a recommendation is intended to achieve, maintain, or avoid); action value (a specified state of an action); and scope (implicit eligibility criteria for an imperative statement). Within the GEM II document model, a new major subtree called Implementation Plan will be added to recognize and promote increasing attention to issues related to guideline implementation. This subtree will accommodate concepts related to anticipated barriers to and enablers of successful operationalization of guideline knowledge, potential implementation modes, and strategies.

(2) The benefits of W3C Schema over DTDs

GEM was conceived and developed as a Document Type Definition (DTD) at a time when the Worldwide Web Consortium (W3C) Schema definition was not yet a standard. The W3C published its XML Schema Recommendation in May 2001. Since that time, developers have made considerable progress in applying Schema effectively. Advantages of W3C Schema for GEM II over the GEM DTD representation include:

(3) A desire to simplify the document architecture and improve clarity

The <document.header > and <document.body> elements, which are children of the root element in GEM, add an unnecessary layer to the model. They were included in the DTD to promote consistency with HL7's Clinical Document Architecture. But it has become clear that guidelines are vehicles for clinical knowledge and are not "clinical documents" applicable to an individual patient in the same way that history and physical examination, laboratory, and consultant reports are. Therefore, header and body elements will be eliminated in GEM II. GEM incorporated concepts from the National Guidelines Clearinghouse (NGC) for which a structured vocabulary had been created for terms that are important for guideline dissemination and indexing. Each of these concepts was associated with a limited structured vocabulary provided by the NGC. In some cases, these structured elements have been confused with other GEM elements that use narrative text to encode overlapping or equivalent content. This redundancy has created dilemmas for GEM users regarding appropriate markup. In addition, the NGC has changed both the names of some of its elements and the structured vocabulary resulting in maintenance difficulties for the model. In GEM II we have extracted the NGC elements from the document hierarchy. In GEM II, we change the dot notation to camelback notation (<committee.name> becomes <CommitteeName>). We have found that the dot notation is confusing when applied in object models where this notation implies methods or properties. As a result of this confusion, some applications did not handle GEM element names as expected.