RATIONALE, AIMS AND OBJECTIVES: This paper deals with the problem of surgical waiting lists and is aimed, in particular, at comparing two different prioritization approaches: (1) the clinical assessment of treatment urgency aimed at categorizing patients into urgency-related groups (URGs) with a given recommended maximum waiting time for treatment; and (2) the implementation of an original prioritization scoring algorithm aimed at determining the relative priority of each patient in the waiting list and the corresponding order of admission. METHODS: A modelling (...) exercise based on a cohort of 236 patients enrolled on the waiting list of a surgical department in an Italian public university hospital, from 1 January to 30 June 2004, is presented. The comparison is based on a measure called need-adjusted-waiting-days, which allows to take into proper account both urgency and priority. RESULTS: The results show that both methods should be implemented simultaneously for increasing the department's performance in terms of both efficiency--outcome gained from a given amount of resources--and equity--how patients are admitted according to their need. CONCLUSIONS: Waiting list prioritization should not be limited to classifying patients into URGs, but to using a scoring system as well, in order to schedule patient admissions in an explicit and transparent way. (shrink)