Productive and Economic Efficiency.

From A&A, P. 10

"The fact that production capability is limited can be expressed by a production possiblity boundary [frontier], which indicates the maximum amount of any particular goood that can be produced within the constraint that specified amounts of other goods are to be produced. Achieving that constraiined production maximum is called technological or productive efficiency.

"Achieving the "best" place on the boundary, that is the best combination of the various production efficient outputs is called economic efficiency"

Economic efficiency required "defining some appropriate criterion of what is best." A&A p.3