Mooers’s Law
Information competes with every other way of getting the same answer, and the winner is usually whichever costs the least effort, not whichever is most accurate.
What Is It?
Formulated by information scientist Calvin Mooers in 1959: “An information retrieval system will tend not to be used whenever it is more painful and troublesome for a customer to have information than for him not to have it.” The mechanism is comparative friction, not accuracy. Information doesn’t have to be difficult to retrieve, it only has to be more difficult than the alternative. Usage is governed by the comparison between the effort of retrieval and the effort of doing without, not by how good the information actually is once found, a mediocre answer available in five seconds often beats an excellent answer hidden behind two minutes of searching. The same principle extends past documentation to dashboards, reporting, analytics, policy manuals, lessons-learned archives, and AI assistants, anywhere a system’s usage depends on retrieval cost rather than content quality.
Why Does It Matter?
Wikis, internal documentation, and knowledge bases routinely fail not because the content inside them is bad but because finding it costs more effort than the alternative people are already using: asking a colleague, re-deriving the answer, or just guessing. Organizations often respond to low usage by writing more documentation, when the actual problem is that nobody wants to retrieve it. Every knowledge system has competitors, whether they were intentionally designed or not, Slack, asking a colleague, memory, guessing, a search engine, an AI assistant, and the real competitor isn’t a better document, it’s whatever path of least resistance people have already found. Seen this way, the central design problem isn’t preserving knowledge, it’s minimizing the effort required to reach it at the moment it’s needed.
What Changes Once You See It?
You stop diagnosing a failing documentation system as a content problem first, and start asking what the actual friction of retrieval is, compared honestly to whatever people are doing instead.
You also start looking for the fix in search, structure, and findability rather than in more writing, since more content doesn’t help if the friction of finding it stays the same, and you become interested in watching where people actually go first when they need an answer, because that’s the real competition your documentation has to beat.
Common Misunderstandings
- It isn’t an argument against documentation. It’s an argument for making documentation genuinely easier to use than the alternative, not just more complete.
- It doesn’t mean every unused system is badly designed. Sometimes the alternative, asking a colleague, is genuinely lower-friction and always will be for certain kinds of questions, and the honest response is accepting that rather than fighting it.
- It isn’t only about search interfaces. Organizational friction, unclear ownership, no obvious place to start, counts just as much as technical friction.
- It doesn’t mean the easiest source is always the best one. People often choose lower-friction information even when it’s less reliable, the law predicts behavior, not optimal behavior.
Diagnostic Question
Is it actually easier to find this than to just ask someone or do without it?
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Field Notes
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Related Field Guide
Origin
Calvin Mooers, “Mooers’s Law: or, why some retrieval systems are used and others are not” (1959), American Documentation.