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Equation 4 · Part 1 · Selection Accounting: The Price Equation Runs the Economy

Symbol w_i

wiw_i
wiw_i

What this part means

wiw_i is a part of this expression. Its role is fixed by the surrounding article and by the operations shown in the formula.

Its job in the formula

wiw_i is a part of this expression. Its role is fixed by the surrounding article and by the operations shown in the formula.

The passage around this formula

The change in mean log productivity splits into a covariance between a firm’s relative fitness — its share-growth factor wiw_i — and its productivity, plus a share-weighted average of each firm’s own productivity change, weighted by how much it grew. The first term is selection: value reallocated toward whoever is already ahead. The second is transmission: value created inside units that already exist. This holds for any partition of any economy in any period. It is exact bookkeeping, not a behavioral model, and it carries no error term to hide behind.

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Learn the underlying idea

A subscript is a label attached below a symbol. It often selects a time step, component, category, or member of a sequence.

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Sources cited in the article section

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