efficiency

Efficiency is the (often measurable) ability to avoid wasting materials, energy, efforts, money, and time in doing something or in producing a desired result. In a more general sense, it is the ability to do things well, successfully, and without waste. In more mathematical or scientific terms, it is a measure of the extent to which input is well used for an intended task or function (output). It often specifically comprises the capability of a specific application of effort to produce a specific outcome with a minimum amount or quantity of waste, expense, or unnecessary effort. Efficiency of course refers to very different inputs and outputs in different fields and industries.

Efficiëntie en effectiviteit zijn twee gerelateerde begrippen met een delicaat maar niettemin belangrijk verschil in de betekenis.
Ze worden regelmatig per abuis door elkaar gebruikt.