calculation of workload

Hi, everybody! In our laboratory, we currently calculate workload according to technican hour spent on a task. However, we want to review whether this is a fair way to compare workload among different laboratories, no matter they are whether in the same discipline or not. I would like to know whether there is a widely accepted system to do this in other countries. I read something about the relative value unit (RVU) for medicare reimbursement. Does anybody think that's a good reflection of the amount of effort spent on a particular task? Are there any on-line websites that I cango to for this information? Any input would be much appreciated. TIA.