A systematic review including 10 RCTs with a total of 2,881 women receiving patient reminders and 7,899 women receiving reminders from GPs was abstracted in DARE. Women who had received GP reminders were more likely to have the test compared with controls, risk difference 6.6% (95% CI 5.2 to 8.0%), NNT 15.2. The summary risk difference for patient reminder studies was 4.9 (95% CI 2.6 to 7.2), NNT 20.3.