DEA (Data Envelopment Analysis) if a subfield of economics that compares the best ideal producer of a given good or service with one or more actual producers. "If the virtual [ideal] producer is better than the original producer by either making more output with the same input or making the same output with less input then the original producer is inefficient. Some of the subtleties of DEA are introduced in the various ways that producers A and B can be scaled up or down and combined." (From the Portland State University website).
