MENTAL MODEL · M0014

Gall's Law

BusinessmediumManagement

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Version 1.0.0 · Updated 2026-07-30

CORE DEFINITION

John Gall’s system-design rule of thumb holds that working complex systems generally evolve from working simple systems, while elaborate systems designed from scratch are prone to failure. Its aphoristic formulation is not a proven universal law without exceptions.

SCAFFOLDING EFFECT

psychology

Reduce cognitive load

Guides project management and product design. It emphasizes the importance of iteration, suggesting that one should first build a minimal simple system that works, then gradually increase complexity, rather than trying to build a perfect large system from the start.

anchor

Anchor fast decisions

As an engineering explanation, a simple working system supplies real feedback and validated interfaces; incremental extension can expose dependencies and design assumptions earlier. Gall’s law summarizes this direction as a rule of thumb rather than proving that complex systems will succeed.

MINIMUM ACTION

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Practice this model in one real situation:

Choose one essential end-to-end task, write acceptance criteria, and implement a minimal working version. Validate it with actual inputs, then add one necessary capability at a time and rerun the original task and new acceptance scenarios. If it fails, first inspect the dependencies just introduced.

Check to track your progress (stored locally)

Learning progress0%

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Source support: Explicit

link
wiki.mbalib.comhttps://wiki.mbalib.com/wiki/%E7%9B%96%E5%B0%94%E5%AE%9A%E5%BE%8BZH · Explicit
verified
link
en.wikipedia.orghttps://en.wikipedia.org/wiki/John_Gall_(author)EN
verified

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