Effect of feedback on test ordering behaviour of general practitioners.

Abstract
OBJECTIVE--To assess the effect of feedback on the test ordering behaviour of general practitioners. DESIGN--Comparison of requests at two diagnostic centres, and internal comparison between tests which were discussed in feedback and tests which were not. SETTING--A diagnostic centre in Maastricht giving feedback and another elsewhere in the Netherlands (laboratory A) not giving feedback. SUBJECTS--All 85 general practitioners in the region of Maastricht, and all general practitioners in the region of laboratory A. MAIN OUTCOME MEASURES--Numbers of tests requested by general practitioners. RESULTS--Requests at the Maastricht diagnostic centre decreased soon after the onset of feedback whereas there was a persistent increase in requests at laboratory A. Tests that were discussed showed the strongest decrease (maximum 40%), though tests that were not discussed decreased as well (maximum 27%). CONCLUSIONS--Feedback on diagnostic requests may exert a strong influence on request behaviour. Four years after the onset of feedback the effects were still noticeable.