Skip to main content
The Incentives Lab
Fallacy · Causation

Post Hoc Ergo Propter Hoc

B followed A, therefore A caused B.

"We launched the campaign and revenue went up. Must have been us."

Quick answer

What is Post Hoc Ergo Propter Hoc? B followed A, therefore A caused B. Attribution theater that distorts the next year's investments.

In the wild

Crediting a turnaround to the new strategy when the market simply recovered.

Why it matters in the room

Attribution theater that distorts the next year's investments.

Visual · Broken inference
P1P2P3P4∴ ?
Post Hoc Ergo Propter Hoc chains valid-looking steps to an invalid conclusion.
Live · Catch post hoc ergo propter hoc

Sales jumped the week after marketing launched a campaign. The campaign lead says 'it worked.' Honestly:

How does this land?

Pick a reaction to Post Hoc Ergo Propter Hoc

One tap. We'll point you at the most useful next surface based on how this hits.

Human Behavior Element™ · HBE Spec

The full taxonomy entry

Every concept in the Atlas uses the same structure — so Post Hoc Ergo Propter Hoc can be compared, recombined, and cited like an element on a periodic table.

About the standard →
F
PH
HBT-F6795
Official name
Post Hoc Ergo Propter Hoc
Fallacy · Causation
Identity
HBT ID
HBT-F6795
Symbol
PH
Official name
Post Hoc Ergo Propter Hoc
Synonyms
Causation
Keywords
Fallacy, Causation, human behavior, incentive design
Version
v1.0
Last updated
Maintained by The Incentives Lab
Classification
Kingdom
Cognition
Domain
Reasoning
Family
Logical Fallacy
Class
Causation
Element
Post Hoc Ergo Propter Hoc
Definition
Scientific
B followed A, therefore A caused B.
Plain-English
B followed A, therefore A caused B.
Feynman
We launched the campaign and revenue went up. Must have been us.
Core principle
B followed A, therefore A caused B.
One-sentence summary
Attribution theater that distorts the next year's investments.
Mechanisms
Psychological
B followed A, therefore A caused B.
Behavioral econ.
Attribution theater that distorts the next year's investments.
Neurological
Reward, threat, and salience circuits bias attention toward the cue.
Evolutionary
Heuristics that paid off in ancestral environments now misfire in modern systems.
Sociological
Group norms and status incentives reinforce the pattern across a team.
Computational
Models trained on biased human signals will replicate and amplify the pattern.
Systems thinking
Feedback loops between metrics, incentives, and behavior lock the pattern in place.
Signals & signature
Inputs (activators)
Crediting a turnaround to the new strategy when the market simply recovered.
Outputs (observable)
Attribution theater that distorts the next year's investments.
Behavioral signature
You see Post Hoc Ergo Propter Hoc when the explanation for a decision sounds reasonable but the outcome keeps repeating.
Behavioral molecules
Often combines with related Atlas entries — see the rail below.
Pathways · before
A goal, metric, or contract clause makes the behavior rational locally.
Pathways · after
Locally rational choices accumulate into a systemic distortion.
Domains where it shows up
  • Business
  • Leadership
  • Government
  • Healthcare
  • Education
  • Sales
  • Marketing
  • AI
  • Negotiation
  • Media
  • Public Policy
  • Relationships
Examples
Everyday
Crediting a turnaround to the new strategy when the market simply recovered.
Modern
Attribution theater that distorts the next year's investments.
Historical
A pattern repeatedly documented since the foundational behavioral science literature on logical fallacy.
Famous experiments
See the References block — primary papers in the Atlas link out to the original studies.
Design principles
How to leverage
Attribution theater that distorts the next year's investments.
How to reduce
Make the perverse payoff visible; remove or invert it.
How to redesign
Redesign the incentive so post hoc ergo propter hoc stops being the path of least resistance.
The Perverse Incentive Lens™
How it's exploited
Organizations weaponize post hoc ergo propter hoc — sometimes deliberately, often by accident — when metrics reward the symptom rather than the outcome.
Common perverse incentives
Volume metrics, short review windows, bonus cliffs, and contracts that pay on activity rather than impact.
Failure modes
When Post Hoc Ergo Propter Hoc dominates, teams optimize for the dashboard while the real outcome quietly degrades.
Incentive redesign
Pay for the outcome you actually want; remove rewards for behavior that only looks like the outcome.
Ethical considerations
Don't engineer post hoc ergo propter hoc into customers, employees, or citizens as a manipulation tactic — design for informed choice instead.
Diagnostic questions
  • Where in our org would Post Hoc Ergo Propter Hoc most often show up unnoticed?
  • Which metric, ritual, or contract clause quietly rewards Post Hoc Ergo Propter Hoc?
  • If we removed every payoff for Post Hoc Ergo Propter Hoc, what behavior would replace it?
  • Who benefits when Post Hoc Ergo Propter Hoc persists — and who pays the cost?
Organizational warning signs
Metrics
A KPI is hit while the underlying outcome stalls or worsens.
Behaviors
People route around the rule rather than challenge it.
Language
'That's just how we do it here.' / 'The system requires it.'
Culture
Naming the pattern is treated as disloyalty.
Red flags
  • People defend the status quo using the language of post hoc ergo propter hoc.
  • Decisions cluster around the easiest narrative rather than the strongest evidence.
  • New data changes the slide deck but not the decision.
  • Anyone naming the pattern is treated as the problem.
Intervention playbook
Immediate
Make the perverse payoff visible to the people creating it.
30-day
Run a small pilot that pays for the outcome, not the proxy.
Long-term
Rewrite the comp plan, contract, or ritual so the right behavior becomes the easy behavior.
AI considerations
Detect
Audit training data and reward signals for the same pattern this element describes.
Avoid amplifying
Don't optimize models on metrics that already encode the perverse incentive.
Counteract
Use the model to surface where the pattern is most active, then redesign the incentive — not the model.
Measurement
Metrics
Outcome-to-proxy ratio over time.
Assessment
The Incentives Lab III Diagnostic.
Survey
Calibrated pulse questions on rules vs. outcomes.
Behavioral signals
Where people work around the system.
Observational
Where the dashboard and the lived experience disagree.
Scientific evidence
Evidence grade
Synthesized from the behavioral science literature; see Atlas references.
Replication
Tracked in the Atlas as primary, replicated, or contested.
Intervention confidence
Moderate — patterns generalize, mechanisms vary by context.
Research consensus
Broad agreement on the pattern; ongoing debate on boundary conditions.
Known limitations
Local context, culture, and incentive structure all change the strength of the effect.
Open questions
How does Post Hoc Ergo Propter Hoc interact with AI-mediated decisions at scale?
References
Meta-analyses
Tracked in the Atlas registry.
Seminal authors
Kahneman, Tversky, Thaler, Ariely, Cialdini, Ostrom, Simon — and the field they built.
Cross references

Every Atlas entry is a node in a knowledge graph. See the related rail below to follow the connections.

Disciplinary layers

See Post Hoc Ergo Propter Hoc through 2 lenses

Each layer of the Incentives OS reframes this concept with its own thinkers, vocabulary, and diagnostic question.

Test yourself · 60 seconds

Do you actually know Post Hoc Ergo Propter Hoc?

Three quick questions. Result is saved into your review streak — come back when the term is due to lock it in.

Question 1 of 2Score: 0/2

Which best describes Post Hoc Ergo Propter Hoc?

Go deeper

Worked example, counter-example & concept map

On-demand AI analysis grounded in the Lab's research. Cached on your device after first run.

How this lands in you

Your nervous system has a region for this.

Primary region
Prefrontal Cortex

When you encounter Post Hoc Ergo Propter Hoc, your prefrontal cortex has to do extra work to override the automatic response — and that override budget is finite.

Executive control, planning, impulse override, working memory, System 2. First thing to go offline under stress, fatigue, or low blood sugar. Why your 4pm decisions are worse than your 9am ones.

See Prefrontal in the Brain Atlas →
You may also like

Picked for you, from the Atlas

Ranked by shared learning paths, overlapping chips, and what you've saved.

Share this rabbit-hole

Send the card, not just the link

A pre-rendered social card with the title, eyebrow, and URL. Copy the link, post it anywhere, or download the SVG for slides.

Keep pulling the thread

More definitions to follow

Every term in the Atlas connects to a dozen others. Pick any of these and see where it takes you.

Keep exploring the Atlas
← Browse the full Atlas