Having done that, we're now in the process of calculating the hours each "work center" has to contribute. We're defining a work center as any group of the same resources. Ten welders with the same skills constitute a work center. Four identical machines constitute another. The four machinists who set up and run the machines are still another, and so on. Dividing the total of work center hours needed, by the number of resources in it, gives us the relative effort per resource, a standard we can use for com- parison.