Factors influencing diagnostic decision-making

Identifying influences on diagnostic decisions is important because diagnostic errors often have far-reaching consequences for an individual's future within the workforce and their eligibility for Accident Compensation Corporation-funded treatment. Most investigations of factors biasing decision making have used quantitative techniques rather than qualitative methods.

To identify factors influencing GPs' diagnostic decision-making and to develop a valid questionnaire to determine the desirability and importance of each factor's influence.

Focus groups and the Delphi method were combined with Rasch analysis to identify factors influencing GPs' diagnostic decision-making and then examine the strength and stability of ratings of the factors' desirability and importance.

Thirty-nine factors were identified. Factors demonstrating high stability but no consensus included the importance of evidence-based medicine, the potential ramifications of a diagnosis, and the desirability of medicolegal issues. Factors for which there was disagreement in the first Delphi round but consensus in the second round included the importance of patient advocacy/support groups and the desirability of examination findings. Rasch analysis indicated that the questionnaire was close to the model (88.6% and 86.2% of variance in the ratings of importance and desirability explained).

Participants readily identified factors influencing GPs' diagnostic decision-making. Their ratings did not appear to support a prescriptive model of medicine, yet two cornerstones of prescriptive medicine, clinical information and probability of disease, were rated as highly desirable and important.