Post Hoc Ergo Propter Hoc is b followed A, therefore A caused B. It sits in the Cognition dimension (COG) of the Human Behavior Taxonomy™ as element HBT-COG-0537, within the Causation Fallacy family. The core principle: b followed A, therefore A caused B. In incentive terms, it matters because it changes the payoff people perceive before they choose — which means it can be designed for, or exploited.
Scientific Definition
B followed A, therefore A caused B.
Plain-English Definition
B followed A, therefore A caused B.
Feynman Explanation
We launched the campaign and revenue went up. Must have been us.
Core Principle
B followed A, therefore A caused B.
Mechanisms
B followed A, therefore A caused B.
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Inputs (Triggers)
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Outputs (Behaviors)
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Behavioral Signature
We launched the campaign and revenue went up. Must have been us.
Examples
- Crediting a turnaround to the new strategy when the market simply recovered.
- Attribution theater that distorts the next year's investments.
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Original analysis from The Incentives Lab — how this element behaves inside real payoff structures.
Why this element matters to incentive design
Executives usually notice this element only after it has cost something. By then it looks like a one-off. It is not. The mechanism underneath it is straightforward: b followed A, therefore A caused B. You can recognize it in the field by its signature: we launched the campaign and revenue went up. Must have been us. Every element in the Cognition dimension changes the perceived payoff of an action before the action happens, which is exactly where incentive design has leverage.
How it gets exploited
Left undesigned, attribution theater that distorts the next year's investments. It is amplified whenever attribution theater that distorts the next year's investments. Inside organizations that shows up as attribution theater that distorts the next year's investments. The pattern is the same one Goodhart's Law describes: the measurable proxy attracts the effort, and the purpose behind it quietly loses funding.
How the Lab designs around it
The redesign move is to make the desired behavior observable, remove whatever currently pays for its opposite, and attach the reward to the behavior rather than to the noisy outcome downstream of it. The leverage is not in explaining the behavior to people. It is in changing what the behavior earns.
Famous Experiments
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Design Principles
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Measurement Approaches
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Evidence
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The Perverse Incentive Lens™
How this behavior is exploited — and how to redesign around it.
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Interactive Mini Network
Click any neighbor to re-center the graph and follow the threads of connection.
Knowledge Graph Neighbors
Auto-linked to the rest of the Human Behavior Taxonomy by family, domain, dimension, and shared keywords.
With this, therefore because of this.
If A then B; B happened; therefore A.
Reasoning backward from outcomes to motives.
Treating two things that move together as one causing the other.
If A then B; not A; therefore not B.
Stacking so many tenuous links that the conclusion sounds clever.
Assuming one cause where many are at play.
A small step inevitably leads to extreme consequences.
Small step → catastrophic outcome, without the intermediate causal links.
Attacking the person rather than the argument.
A single story used as proof of a general claim.
It's true because authority says so.
Where Post Hoc Ergo Propter Hoc is cited in the corpus
Essays, field guides, and diagnostics from The Incentives Lab that apply this element.
- EssayGoodhart's Law in the Real World
How measurable proxies capture judgment.
- EssayThe Perverse Incentives Hiding in Your KPIs
Cognitive shortcuts turned into scorecards.
- CourseIncentives 101
The free ten-part primer on reading a payoff structure.
- ReferenceThe incentive glossary
Definitions for every mental model, bias, and fallacy in the corpus.
- ReferenceThe Periodic Table of Human Behavior
The full 1,267-element map this page belongs to.
Questions about Post Hoc Ergo Propter Hoc
- What is Post Hoc Ergo Propter Hoc?
- Post Hoc Ergo Propter Hoc is b followed A, therefore A caused B. It sits in the Cognition dimension (COG) of the Human Behavior Taxonomy™ as element HBT-COG-0537, within the Causation Fallacy family. The core principle: b followed A, therefore A caused B. In incentive terms, it matters because it changes the payoff people perceive before they choose — which means it can be designed for, or exploited.
- What is an example of Post Hoc Ergo Propter Hoc?
- Attribution theater that distorts the next year's investments. The Incentives Lab catalogs everyday, organizational, and historical instances of this element on its Human Behavior Taxonomy™ page (HBT-COG-0537).
- How is Post Hoc Ergo Propter Hoc exploited?
- Attribution theater that distorts the next year's investments.
- How do you design around Post Hoc Ergo Propter Hoc?
- Name the behavior you want in observable terms, remove what currently pays for the opposite, attach the reward to the behavior rather than a lagging proxy, and publish how you will detect gaming.
- Which behavioral dimension does Post Hoc Ergo Propter Hoc belong to?
- Post Hoc Ergo Propter Hoc is classified in the Cognition dimension (COG) of the Human Behavior Taxonomy™, family "Causation Fallacy", class "Logical Fallacy". Its permanent identifier is HBT-COG-0537 and its evidence grade is B.