Conjunction Errors: 10 Evidence-Based Coaching Practices
Describe almost anything you are working through and IX Coach finds the practices whose real-world fit is closest. For Conjunction Errors, these are the strongest matches in the current practice library.
About 2 minutes
Try it here: list the parts that must all happen
List the parts of a plan that all have to happen for it to work. Judging each part on its own shows where the risk sits.
Which parts of your plan all have to happen?
Practices that may help
- Red-team joint scenarios before betting on them
Before acting on a conjunction ("X will happen AND Y will follow"), assign a skeptic to attack the "and."
The Conjunction Fallacy — When "More Details" Feels More Likely - Test each component probability separately
Before judging a joint claim, estimate each element on its own, then check whether the conjunction is lower.
The Conjunction Fallacy — When "More Details" Feels More Likely - The Conjunction Fallacy — When "More Details" Feels More Likely
The conjunction fallacy is the well-replicated tendency to judge a specific combination of events as more probable than one of its components alone — made famous by Kahneman and Tversky’s Linda problem. It happens because vivid, representative details hijack probability judgment, and the fix is to reason about base rates rather than narrative fit. - Audit plans for scenario inflation
Before committing to a plan that depends on multiple things going right, count the dependencies.
The Conjunction Fallacy — When "More Details" Feels More Likely - Explicitly distinguish coherence from probability
A story can be internally consistent and still be rare — learn to separate "makes sense" from "likely."
The Conjunction Fallacy — When "More Details" Feels More Likely - Consult an outside observer to counteract narrative pull
Describe the scenario to someone who doesn’t share your narrative context and listen to their probability estimate.
The Conjunction Fallacy — When "More Details" Feels More Likely - Treat errors as adjacent-possible expansion events
When something goes wrong, ask what new territory the failure has made visible that success would have hidden.
The Adjacent Possible, Made Practical - Rule out mind-reading and fortune-telling
Catch the two most common interpretation errors — assuming you know what someone is thinking, or what is about to happen.
Check the Facts, Made Practical - Anchor on base rates before adding details
Start with how common the outcome is in the relevant population, then update — don’t start with the story.
The Conjunction Fallacy — When "More Details" Feels More Likely - Build branches that are MECE at every level
Ensure each set of branches is mutually exclusive (no overlap) and collectively exhaustive (nothing important missing).
Issue Tree Analysis
Does this sound like the set of challenges you might be facing?
- I’m betting on "this will happen and then that will follow," and the link between them feels airtight to me
- When two things fit together neatly in my head, I treat the whole package as more likely than either piece alone
- My plan only works if a whole chain of things all go right
- Because I can explain exactly why something would happen, I treat it as likely to happen
- I’ve lived inside this scenario so long that every piece feels obvious to me
Related concerns
- Conjunction Error Probability
Before judging a joint claim, estimate each element on its own, then check whether the conjunction is lower.
Test each component probability separately
- Conjunction Fallacy Practice
Before judging a joint claim, estimate each element on its own, then check whether the conjunction is lower.
- The Conjunction Fallacy When More Details Feels More Likely After A Setback
The conjunction fallacy is the well-replicated tendency to judge a specific combination of events as more probable than one of its components alone — made famous by Kahneman and Tversky’s Linda problem. It happens because vivid, representative details hijack probability judgment, and the fix is to reason about base rates rather than narrative fit.
- The Conjunction Fallacy When More Details Feels More Likely At Work
The conjunction fallacy is the well-replicated tendency to judge a specific combination of events as more probable than one of its components alone — made famous by Kahneman and Tversky’s Linda problem. It happens because vivid, representative details hijack probability judgment, and the fix is to reason about base rates rather than narrative fit.
- Why A Detailed Scenario Feels More Likely Than A Simple One
Translate the vivid scenario into a dry statistical question to see if it still feels probable.
Strip the narrative and restate as a bare frequency claim
- Conjunction Planning Error
Before committing to a plan that depends on multiple things going right, count the dependencies.
Audit plans for scenario inflation
Describe your situation in your own words to search the complete practice library.