A Qualifier

"Economic efficiency" is a powerful economic concept used when discussing the distribution of resources. Yet it is often misused and misunderstood in how it is applied in practice. Also often poorly understood are the strengths and limitations of economic efficiency alone as a guide to practical public policy-making, and the relationship of economic efficiency to social justice.
The usual definitions of economic efficiency are generally obscure. It can be argued that economic efficiency is "oversold" at the expense of other societal objectives and is misleading in other ways as well, notably concerning how economic efficiency is usually measured in practice. The usual definitions generally define economic efficiency in terms of the ability of those who gain from a change to fully compensate those who lose from it and still be better off.