Fudge factor

Fudge factor

Fudge factors are invented variables whose purpose is to force a "calculated" result to give a better match to what happens in the real world.

Fudge factors are usually calculated "retrospectively", and when a calculation has only managed to produce a good match to real data by the addition of a variable that seems artificially tailored to allow that result (to allow the calculations to be "fudged" to give the right answer), critics may sometimes refer to the variable in an uncomplimentary way as a "fudge factor".

The term "fudging" meaning to falsify information in order to impress others is derived from this concept [ [http://dictionary.reference.com/browse/fudging fudging - Definitions from Dictionary.com ] ] .

Examples in science

Some variables in scientific theory are set arbitrarily according to measured results rather than by calculation (for example, Planck's constant). However, in the case of these fundamental constants, their arbitrariness is usually explicit. To suggest that other calculations may include a "fudge factor" may suggest that the calculation has been somehow tampered with in order to make the results give a misleadingly good match to the experimental data.

Cosmological constant

In theoretical physics, when Einstein originally tried to produce a general theory of relativity, he found that the theory seemed to predict the gravitational collapse of the universe: it seemed that the universe should either be expanding or collapsing, and in order to produce a model in which the universe was "static and stable" (which seemed to Einstein at the time to be the "proper" result), he introduced an expansionist variable (called the Cosmological Constant) whose sole purpose was to cancel out the cumulative effects of gravitation.

Dark matter

Currently there is some controversy over the disagreement between general relativity's predictions and the available astronomical data: In some situations, gravitational effects seem to be acting more powerfully than GR predicts. The current mainstream explanation is that the universe contains a certain amount of unseen dark matter of unknown composition. Due to the vagueness of this explanation, it is not yet clear whether the "dark matter" explanation represents a real discovery, or whether it is an arbitrary "fudge factor" invented to explain away the discrepancy between theory and experiment.

Expected error margins

A common feature of "fudge factors" in science is their arbitrariness, and their retrospective nature.

However, in project management it's common to build a certain error margin into the "predicted" "resource cost" of a project in order to make predictions more realistic: there are many unforeseen factors that may delay a project or make it more costly, but very few factors that could result in it being delivered "before" time or "under" the calculated budget ... so to some degree, "unexpected" overruns are to be expected, even if their precise nature can't be predicted in advance. Experienced planners may know that a certain type of project will tend to overrun by a certain percentage of its calculated resource requirements, and may multiply the "ideal" calculations by a safety margin to produce a more realistic estimate, and this margin may sometimes be referred to as a fudge factor. However, when planning ahead for "expected" unpredictabilities, these "error margins" are usually assigned other, more specific names : for instance in warehouse stock control, where a certain amount of stock is expected to disappear naturally through damage, pilfering or other unexplained problems, the discrepancy is referred to as shrinkage.

References


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Look at other dictionaries:

  • fudge factor — fudge factor, n. a term or factor inserted into a calculation to compensate for anticipated errors, or to arbitrarily make the result conform to some desired conclusion. [PJC] …   The Collaborative International Dictionary of English

  • fudge factor — n. a margin of error. □ I never use a fudge factor. I measure correctly, and I cut the material exactly the way I measured it. □ I built in a fudge factor of three inches …   Dictionary of American slang and colloquial expressions

  • fudge factor — noun a) A quantity introduced to compensate for uncertainty. We dont know exactly how much the load will weigh, so well add in a fudge factor to make sure we dont underestimate. b) any padding or compensation built into a guess or estimate …   Wiktionary

  • fudge factor — noun Date: 1962 an arbitrary mathematical term inserted into a calculation in order to arrive at an expected solution or to allow for errors especially of underestimation; broadly any arbitrary unspecified factor …   New Collegiate Dictionary

  • fudge factor — any variable component added to an experiment, plan, or the like that can be manipulated to allow leeway for error. * * * …   Universalium

  • fudge factor — /ˈfʌdʒ fæktə/ (say fuj faktuh) noun the amount by which a budget or estimate of costs has been adjusted to make it seem acceptable …  

  • fudge factor — noun a quantity that is added or subtracted in order to increase the accuracy of a scientific measure • Syn: ↑correction • Hypernyms: ↑indefinite quantity …   Useful english dictionary

  • Fudge (disambiguation) — * Fudge, a type of confectionery, usually made with sugar, milk, butter and flavoring, often chocolateFudge may also refer to:Real People* Georgia Fudge, an American female bodybuilderFictional People* Cornelius Fudge, the fictional Minister for… …   Wikipedia

  • Fudge (homonymie) — Cette page d’homonymie répertorie les différents sujets et articles partageant un même nom. Fudge est un mot anglais pour une confiserie le verbe bousiller Ce mot anglais est employé dans l expression GTFO (Get The Fudge Outtahere) ; voir… …   Wikipédia en Français

  • Fudge — La palabra inglesa fudge puede referirse a: Fudge, el dulce de azúcar; Fudge, acrónimo que da su nombre a un sistema genérico de juego de rol; Fudge, un área no incorporada de Estados Unidos; Fudge, una serie de televisión estadounidense; Fudge… …   Wikipedia Español

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