Table 3
Frequency and description of knowledge model types used by studies
| Knowledge model | Description |
| Document model (5 studies, 1 system implemented93) | Human readable document with concepts represented in situ, usually preserving the original structure of the source document (Guideline Elements Mode (GEM) or other document-centric extensible mark-up language (XML) schema) |
| Semantic web (9 studies, 6 systems implemented64 69 74 89 108 119) | Models proposed by the world wide web consortium (W3C) for representing information on the web (web ontology language (OWL) ontologies, Semantic Web Rule Language (SWRL) rules, OWL-S web services) |
| Formal workflow model (8 studies, 3 systems implemented4 71 92) | Formalized workflow constructs underpinned by a formal mathematical model (Petri Nets, Yet Another Workflow Language (YAWL)) |
| Object model (8 studies, 2 systems implemented36 110) | Object-oriented techniques to model collection of hierarchical, interacting classes that represent guideline, workflow, or pathway concepts (Unified Modeling Language (UML), HL7 Reference Information Model (RIM), openEHR) |
| General task-network model (14 studies, 4 systems implemented14 50 103 104) | Flowcharts or process maps without formal semantics (Program Evaluation Review Technique/Critical Path Method (PERT/CPM), activity-on-node) |
| General workflow model (14 studies, 11 systems implemented3 39 74 91 93 103 104 114 118 129 134) | General workflow semantics (Business Process Modeling Notation (BPMN), Business Process Execution Language (BPEL)) |
| Block-structured, procedural, logic rules (20 studies, 11 systems implemented3 43 51 65 72 84 96–98 101 109) | Block-structured, procedural programming languages, and IF…THEN rules (Arden Syntax; decision tables) |
| Formal task-network model (48 studies, 23 systems implemented4 36 40 45 54 57 59 61 62 71 75 78 79 87 89 95 99 111 118 121 126 131 135) | Guideline-based clinical tasks—actions, decisions, queries—that unfold over time, with a formal syntax and semantics (Guideline Interchange Format (GLIF), PROforma, Asbru) |
