# Efficiency

Efficiency in general describes the extent to which time, effort or cost is well used for the intended task or purpose. It is often used with the specific purpose of relaying the capability of a specific application of effort to produce a specific outcome effectively with a minimum amount or quantity of waste, expense, or unnecessary effort. "Efficiency" has widely varying meanings in different disciplines.

The term "efficient" is very much confused and misused with the term "effective". In general, efficiency is a measurable concept, quantitatively determined by the ratio of output to input. "Effectiveness", is a relatively vague, non-quantitative concept, mainly concerned with achieving objectives. In several of these cases, efficiency can be expressed as a result as percentage of what ideally could be expected, hence with 100% as ideal case. This does not always apply, not even in all cases where efficiency can be assigned a numerical value, e.g. not for specific impulse.

A simple way of distinguishing between Efficiency and Effectiveness is the saying, "Efficiency is doing things right, while Effectiveness is doing the right things." This is based on the premise that selection of objectives of a process are just as important as the quality of that process.

A slightly broader mode of efficiency that nevertheless remains consistent with the "percentage" definition in many cases is to say that efficiency corresponds to the ratio r=P/C of the amount P of some valuable resource produced, per amount C of valuable resources consumed. This may correspond to a percentage if products and consumables are quantified in compatible units, and if consumables are transformed into products via a conservative process. For example, in the analysis of the energy conversion efficiency of heat engines in thermodynamics, the product P may be the amount of useful work output, while the consumable C is the amount of high-temperature heat input. Due to the conservation of energy, P can never be greater than C, and so the efficiency r is never greater than 100% (and in fact must be even less at finite temperatures).

### Other articles related to "efficiency":

International Partnership For Energy Efficiency Cooperation - Initiatives
... AEEFM - Assessment of Energy Efficiency Finance Mechanisms (led by India) AEEFM seeks to identify and document methods to overcome the multiple barriers that impede the successful and widespread financing of energy ... In particular, AEEFM is currently examining how energy efficiency projects can better utilize financing from domestic sources, such as commercial banks ... EMAK - Energy Management Action Network for Industrial Efficiency (led by Japan) EMAK is working on creating a forum to promote energy management in industry ...
Material Efficiency
... Material efficiency is a description or metric which expresses the degree in which usage of raw materials, construction projects or physical processes are used or carried out in a manner ... stock than a prior version increases the material efficiency of the manufacturing process ... The term Material efficiency can also signify the degree in which a material can handle a particular load, strain or weight upon it ...
Efficiency - In Science and Technology - In Other Sciences
... In computing Algorithmic efficiency, optimizing the speed and memory requirements of a computer program Storage efficiency, effectiveness of computer data ...
International Partnership For Energy Efficiency Cooperation
... The International Partnership for Energy Efficiency Cooperation (IPEEC) is a high-level international forum which includes developed and developing ... enhance global cooperation in the field of energy efficiency (EE) and to facilitate policies that yield energy efficiency gains across all sectors globally ... a key milestone in the improvement of energy efficiency, generally referred to as the use of the least amount of energy per unit of production and/or population ...