Costs can and must be a component of surgical audit.

The cost of running a surgical firm at Addenbrooke's Hospital in Cambridge was assessed over a 1 month period in May 1989. The total of 97,380 pounds was much more than expected for a firm of one full-time and one part-time consultant. It related to the month's workload of 101 admissions, 656 inpatient days, 92 operations and 442 outpatient visits. The derivation of a simple formula enabled individual patient episodes to be costed; from this new data and information stored routinely on the firm's audit system. It has been used to cost patients undergoing procedures commonly performed by the firm and also to illustrate the effect of complicated surgery on resources. Audit has been shown to have potential in a clinician's assessment of his resource use. Its future development in this role is strongly advocated.