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 ...

is the extent to which time or effort is well used for the intended task or purpose. Efficiency may also refer to: *

Efficiency (aerodynamics) In aerodynamics, the lift-to-drag ratio (or L/D ratio) is the lift generated by an aerodynamic body such as an aerofoil or aircraft, divided by the aerodynamic drag caused by moving through air. It describes the aerodynamic efficiency under give ...

, the amount of lift divided by the aerodynamic drag *

Efficiency (apartment) A studio apartment, also known as a studio flat ( UK), a self-contained apartment ( Nigeria), efficiency apartment, bed-sitter ( Kenya) or bachelor apartment, is a small apartment (rarely a condo) in which the normal functions of a number of ...

, a one-room apartment *

Efficiency (basketball) In professional basketball, the most commonly used statistical benchmark for comparing the overall value of players is called efficiency. It is a composite basketball statistic that is derived from basic individual statistics: points, rebounds, as ...

, a statistical benchmark to compare the overall value of players *

Efficiency (economics) In microeconomics, economic efficiency, depending on the context, is usually one of the following two related concepts: * Allocative or Pareto efficiency: any changes made to assist one person would harm another. * Productive efficiency: no addit ...

, a situation in which nothing can be improved without something else being hurt **

Efficiency (fair division) Pareto efficiency or Pareto optimality is a situation where no action or allocation is available that makes one individual better off without making another worse off. The concept is named after Vilfredo Pareto (1848–1923), Italian civil engine ...

, any changes made to assist one person would harm another *

Efficiency (finance) In finance, marginal conditional stochastic dominance is a condition under which a portfolio can be improved in the eyes of all risk-averse investors by incrementally moving funds out of one asset (or one sub-group of the portfolio's assets) and in ...

, non-mean-variance portfolio analysis, a way of showing that a portfolio is not efficient * Efficiency (mechanical) *

Efficiency (network science) In network science, the efficiency of a network is a measure of how efficiently it exchanges information and it is also called ''communication efficiency''. The underlying idea (and main assumption) is that the more distant two nodes are in the ...

, a measure of how efficiently a network exchanges information *

Efficiency (statistics) In statistics, efficiency is a measure of quality of an estimator, of an experimental design, or of a hypothesis testing procedure. Essentially, a more efficient estimator, needs fewer input data or observations than a less efficient one to achie ...

, a measure of quality of an estimator, experiment, or test *

Energy efficiency (physics) Energy conversion efficiency (''η'') is the ratio between the useful output of an energy conversion machine and the input, in energy terms. The input, as well as the useful output may be chemical, electric power, mechanical work, light (radi ...

, the ratio of power consumed to useful power output

See also