# Law of Requisite Variety ## The Idea in Brief Only variety can absorb variety. If your environment throws ten different challenges at you, you need at least ten different responses. A regulator that's simpler than its environment will eventually be overwhelmed. This is Ashby's law, and it explains why rigid systems fail in complex environments—and why adding rules often makes things worse. --- ## Key Concepts ### Variety as Complexity Variety means the number of distinct states a system can be in. A chess board has enormous variety. A thermostat has very little. The environment your organisation operates in has a certain variety; your management system has a certain variety. When the gap is too large, you lose control. ### Two Ways to Close the Gap **Attenuation** — Reduce the variety of the environment. Standardise inputs. Refuse edge cases. Set boundaries. This works until the environment refuses to cooperate. **Amplification** — Increase your own variety. Train people to handle more situations. Build flexible systems. Delegate authority so local controllers can adapt. This is harder but more robust. Most bureaucracies try attenuation because it's easier to design. They write more rules, add more checkboxes, eliminate discretion. But every rule that can't flex is a failure waiting to happen when conditions change. ### The Managerial Implication You can't control what you can't match in complexity. A CEO who insists on approving every decision becomes the bottleneck—they're a low-variety controller trying to manage a high-variety organisation. The solution is to push variety down: give people at the edge the authority and capability to respond to what's in front of them. --- ## Implications **In design:** Systems that demand uniformity from a diverse environment will fail. Design for flexibility, not compliance. **In leadership:** Your job isn't to make every decision. It's to ensure the people making decisions have enough variety in their responses. Train broadly. Delegate appropriately. **In automation:** Rigid scripts break when conditions change. The more automated your system, the more you need exception-handling that matches environmental variety. --- ## Sources - [[The Unaccountability Machine]] — Dan Davies applies requisite variety to explain why organisations lose the ability to adapt - [[Systemantics]] — Gall's complementary insight: systems grow to fill available variety, then become rigid - [[Requisite Organization]] — Elliott Jaques on matching organisational complexity to task complexity --- ## See in Notes - [Variety Kills Flow](https://www.anishpatel.co/variety-kills-flow/) — Hidden cost of variety; context switching, different monitoring points