Published equation contexts
Why this formula appears here
The formal relationship goes back to Theodore Wright’s 1936 observation that aircraft manufacturing labor hours fell as a power-law function of the number of airframes already built, and Way et al. build their entire forecasting method on a stochastic version of it, fitted to more than fifty technologies’ historical cost and production records [ 1 ] . Written in its cleanest form, cost c at cumulative production (experience) z relates to a reference cost at reference experience by: . where the experience exponent b sets the learning rate LR = 1 - 2^{-b} , the fractional cost drop for every doubling of z . Way et al.'s working version of the same relationship is…
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Symbol z
z is an argument of the function-like quantity on the left; its role is set by that function’s stated inputs.
Read this term in its guide →Symbol c_0
is one of the signed contributions combined to compute the quantity on the left.
Read this term in its guide →Symbol z_0
occurs below the fraction bar. The quantity above the bar is divided by this expression; zero is excluded as a denominator.
Read this term in its guide →Symbol b
b is one of the signed contributions combined to compute the quantity on the left.
Read this term in its guide →How to interpret it
With a fixed numerator, increasing a nonzero denominator reduces the fraction. Read it with the definitions, units, and assumptions supplied by the article.
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Published contexts (1)
A symbol can carry a different meaning in another article. Each occurrence keeps its own guide and term definitions.
Equation 5 · Technological Evolution
The Metabolism of Civilization: Energy to 2100
This equation states an equality: the expressions on both sides have the same value under the article’s assumptions.
The formal relationship goes back to Theodore Wright’s 1936 observation that aircraft manufacturing labor hours fell as a power-law function of the number of airframes already built, and Way et al. build their entire forecasting method on a stochastic version of it, fitted to more than fifty technologies’ historical cost and production records [ 1 ] . Written in its cleanest form, cost c at cumulative production (experience) z relates to a reference cost at reference experience by: . where the experience exponent b sets the learning rate LR = 1 - 2^{-b} , the fractional cost drop for every doubling of z . Way et al.'s working version of the same relationship is…