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For example, the state of California began implementing energy-efficiency measures in the mid-1970s, including building code and appliance standards with strict efficiency requirements. During the following years, California's energy consumption has remained approximately flat on a per capita basis while national US consumption doubled. [ 9 ]
For finite values of , the efficiency is higher than this (for example, a sample size of 3 gives an efficiency of about 74%). [citation needed] The sample mean is thus more efficient than the sample median in this example. However, there may be measures by which the median performs better.
Efficiency is very often confused with effectiveness. In general, efficiency is a measurable concept, quantitatively determined by the ratio of useful output to total useful input. Effectiveness is the simpler concept of being able to achieve a desired result, which can be expressed quantitatively but does not usually require more complicated ...
There are also other definitions and measures. All characterizations of economic efficiency are encompassed by the more general engineering concept that a system is efficient or optimal when it maximizes desired outputs (such as utility ) given available inputs.
It has been noted that improvements in resource efficiency can occur at production, consumption, and end of product life stages. [2] Resource efficiency measures, methods, and aims are quite similar to those of resource productivity/resource intensity and of the slightly more environmentally-inclined concept of ecological efficiency/eco-efficiency.
Energy conversion efficiency depends on the usefulness of the output. All or part of the heat produced from burning a fuel may become rejected waste heat if, for example, work is the desired output from a thermodynamic cycle. Energy converter is an example of an energy transformation.
The efficiency ratio indicates the expenses as a percentage of revenue (expenses / revenue), with a few variations – it is essentially how much a corporation or individual spends to make a dollar; entities are supposed to attempt minimizing efficiency ratios (reducing expenses and increasing earnings). The concept typically applies to banks.
Health care efficiency is a comparison of delivery system outputs, such as physician visits, relative value units, or health outcomes, with inputs like cost, time, or material. Efficiency can be reported then as a ratio of outputs to inputs or a comparison to optimal productivity using stochastic frontier analysis or data envelopment analysis .