Programming systems product (Brooks)

Fred Brooks’s name for software that is both a product others can use and a system that fits with others; about nine times the cost of a working program.

In The Mythical Man-Month (1975), Brooks estimates that turning a program into a product (tested, documented, usable by others) costs about three times as much, and into a system component (interfaces, integration) also about three times; both together, about nine times. That is the gap between an AI-built demo that works for its author and software customers pay for.

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Related terms

MVP (minimum viable product): The smallest version of a product that tests whether people want it enough to use or pay.
Technical debt: Shortcuts in code and design that speed up delivery now and make every later change slower until they are paid back.
Cone of uncertainty: How wide an honest estimate is at each stage: from 0.25× to 4× at the idea stage, narrowing as decisions are made.

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