Self-regulation in hospital waiting lists.

There is evidence that hospital waiting lists in the UK are resistant to shortening because reductions in length generate increases in referrals. We explored this concept by examining outpatient data for eight specialties in a large hospital centre over 17 months. Correlation coefficients were calculated by regressing waiting list density (numbers waiting more than 26 weeks) against referral rate. In three of the eight specialties, with the longest waiting lists, referral rates were significantly related, after one month's delay, to waiting list density (P < 0.01)--dermatology, R=0.68; ear-nose-throat R=0.78; trauma/orthopaedics (R=0.64). These were the three with the longest lists. These results help to explain why initiatives to shorten waiting lists are commonly ineffective in the long term.