The formula for project evaluation & review technique (PERT) is Optimistic +(4*MostLikely)+Pessimistic/6. My goal is to add a field to automatically calculate this based on the min, max & average durations of actual tasks. For example, to find the PERT for inspections, I tried to use =[MinInspection]+4*[AvgInspection]+[MaxInspection]/6, but I get a #Name error message. Any suggestions would be greatly appreciated.