Kelley Blue Book

Kelley Blue Book is a long-established U.S. vehicle-valuation guide, first published in 1926, that buyers, sellers, dealers, lenders, and insurers cite as a neutral reference for what a car is worth.

Its authority comes from aggregating large volumes of real transaction and market data into trusted reference values that unrelated parties accept as a common basis.

It is a frequent analogy for WorkForce: a neutral, widely-cited valuation reference for a category of asset — here, AI labor instead of cars.