Modelling diagnosis in physical therapy: a blackboard framework and models of experts and novices

The primary objective of this study was to explore clinical reasoning in physical therapy and to highlight the similarities and differences by modelling the diagnostic phase of clinical reasoning. An experimental design comparing expert and novice physical therapists was utilized. Concurrent verbal protocols detailing the clinical reasoning about standardized case material were elicited. A framework for modelling diagnosis was specified and provided the parameters for analysis. The diagnostic utterances were classified as cues or hypotheses and the knowledge utilized was identified. The experts recruited significantly more knowledge than the novices (p = 0.01) and used more cues (p < 0.01). Their diagnoses were more accurate when compared to the original diagnosis. This difference between the experts and novices was reflected in the differences shown in the models (p < 0.01). The differences between these subjects focused upon the knowledge recruitment, which impacted on the accuracy of the diagnosis. The novices' inaccurate or non-existent diagnoses led to poor quality of treatment prescription. Modelling proved to be a useful way of representing these differences.