Generating pre-test probabilities: a neglected area in clinical decision making.

Objective: To assess the accuracy and variability of clinicians' estimates of pre-test probability for three common clinical scenarios.

Design: Postal questionnaire survey conducted between April and October 2001 eliciting pre-test probability estimates from scenarios for risk of ischaemic heart disease (IHD), deep vein thrombosis (DVT), and stroke.

Participants And Setting: Physicians and general practitioners randomly drawn from College membership lists for New South Wales and north-west England.