[ThinkBetter](https://thinkbetter.app/) → [Cognitive Biases](https://thinkbetter.app/cognitive-biases.md) → Base Rate Fallacy

# Base Rate Fallacy

Ignoring general (usually statistical) information (base rates) in favor of specific anecdotes or recent examples when making decisions.

![Base Rate Fallacy illustration](https://assets.thinkbetter.app/images/base_rate_fallacy.png)

The Base Rate Fallacy occurs when individuals prioritize specific, anecdotal evidence or recent instances over generalized, statistical data when evaluating the likelihood of events. This cognitive bias highlights our tendency to overlook broader spectrum, general information (the base rate) in favor of vivid, personal stories or recent experiences. For example, after hearing a dramatic story about a plane crash, someone might overestimate the dangers of air travel, despite statistics showing it's one of the safest modes of transportation. This bias stems from our brain's preference for narrative and personal experiences, specially if accompanied by imagery or relatable items, over abstract data, making us more susceptible to misjudging probabilities and making irrational decisions. The concept has roots in the field of probability and statistics, significantly influencing how we perceive risk and make decisions in uncertain conditions.

## Example

**Healthcare Decisions**

Choosing not to vaccinate based on stories of rare adverse reactions, ignoring the statistically low risk compared to the benefits. Why? Acknowledging base rates would highlight the overall safety and effectiveness of vaccines.

## In your professional life

**Set Realistic Goals Using Benchmarks**

As an employee, leverage industry benchmarks and historical data to contextualize your performance metrics. For example, if you’re a salesperson, knowing the average conversion rate in your industry helps you set realistic sales targets. This approach ensures your goals are both challenging and attainable, aligning your efforts with industry standards and making your contributions more valuable.

## Go deeper in ThinkBetter

The ThinkBetter app has the full Base Rate Fallacy deep-dive: more examples, a quiz to test yourself, audio narration, and a weekly path that builds these ideas into a habit.

- iOS: https://apps.apple.com/app/id6459831884
- Android: https://play.google.com/store/apps/details?id=io.ventureship.braintricks

### Related concepts

- [Survivorship Bias](https://thinkbetter.app/cognitive-biases/survivorship-bias.md)
- [Bayes' Theorem (Mental model)](https://thinkbetter.app/mental-models/bayes-theorem.md)
- [Probabilistic Thinking (Mental model)](https://thinkbetter.app/mental-models/probabilistic-thinking.md)
- [All mental models](https://thinkbetter.app/mental-models.md)

Page: https://thinkbetter.app/cognitive-biases/base-rate-fallacy