General practitioners' referral thresholds and choices of referral destination: an experimental study

General practitioners (GPs) exert a major impact on NHS resource use, both as providers of primary care and as referrers to secondary care. Referral rates are subject to wide variations, leading to the conjecture that certain GPs may have different 'referral thresholds' from those of others. In this paper, the authors describe an experiment designed both to test the referral threshold hypothesis and to illuminate the GP's decision process with respect to choice over referral destination. Nottinghamshire GPs were provided with hypothetical case histories and a list of possible referral destinations, specifying a range of consultants, their specialist interests, plus the expected waiting times and costs for both out-patient investigation and in-patient treatment. For each case, respondents were requested to indicate whether or not they would refer the patient, and to whom. Respondents were also asked to indicate the extent to which their choices of consultants generally were governed by the specialist interest, the waiting time and the cost information. The responses of the sample support the referral threshold conjecture, with specialist interests and waiting time appearing to be far more important than cost in influencing choice of referral destination. The possibilities of influencing GPs' referral behaviour are discussed, in the light of recent initiatives with respect to prescribing.