Coaching practices for How to Use Base Rates
Describe almost anything you are working through and IX Coach finds the practices whose real-world fit is closest. For How to Use Base Rates, these are the strongest matches in the current practice library.
Does this sound like the set of challenges you might be facing?
- I build my estimate from my own optimistic story first and only glance at how long these things usually take at the very end as a sanity check
- One story has completely sold me on something and I’m about to act on it
- I keep hearing about the handful of people this worked out for and it’s pulling me in
- When I look for examples of people who did what I’m about to do, all I find are the success stories
- I always build my whole story first
Practices that may help
- Base-Rate Neglect: Why We Ignore the Odds
Base-rate neglect is the tendency to underweight or ignore prior probabilities (how often things happen in general) when vivid, specific information is available. Identified by Kahneman and Tversky, it is one of the most robustly replicated biases in judgment research, and it leads to systematic overconfidence in predictions about specific cases. Correcting it requires actively looking up or estimating base rates before evaluating individual information. - Anchor on the base rate before adding inside-view details
Start your forecast from the class median, then adjust — do not start from your narrative and adjust to the base rate.
Reference Class Forecasting - Ask the base rate before evaluating the specific case
Before judging any individual instance, first establish how often this kind of thing happens in general.
Base-Rate Neglect: Why We Ignore the Odds - Reference Class Forecasting
Reference class forecasting, developed by Daniel Kahneman and Amos Tversky and formalized by Bent Flyvbjerg, improves forecast accuracy by anchoring on the statistical distribution of outcomes for similar past projects rather than on the details of the current one. The method reliably corrects the optimism bias that inflates cost, time, and benefit estimates in planning — the evidence base here is real and specific. - Always identify the denominator when evaluating risk or success
When a number or story is striking, ask: "Out of how many total cases?"
Base-Rate Neglect: Why We Ignore the Odds - Actively seek disconfirming cases
When researching base rates, specifically look for cases where things went badly — failure cases are underrepresented in natural memory.
The Outside View - Lead with statistics, then interpret with narrative — not the reverse
Use the base rate as your anchor, then adjust for your specific situation — not the other way around.
The Availability Heuristic: Why Memorable Feels Probable - Use precise, non-round numbers in final offers
A specific non-round number signals calculation and research, not an arbitrary position.
The Ackerman Method, Made Practical - Conduct post-project debriefs to contribute to the class data
Record actual vs. forecast outcomes honestly — this builds the reference class that future forecasts depend on.
Reference Class Forecasting - 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
Related concerns
- Building Base Rate Data
Base-rate neglect is the tendency to underweight or ignore prior probabilities (how often things happen in general) when vivid, specific information is available. Identified by Kahneman and Tversky, it is one of the most robustly replicated biases in judgment research, and it leads to systematic overconfidence in predictions about specific cases. Correcting it requires actively looking up or estimating base rates before evaluating individual information.
- Base Rate Business
Base-rate neglect is the tendency to underweight or ignore prior probabilities (how often things happen in general) when vivid, specific information is available. Identified by Kahneman and Tversky, it is one of the most robustly replicated biases in judgment research, and it leads to systematic overconfidence in predictions about specific cases. Correcting it requires actively looking up or estimating base rates before evaluating individual information.
- Base Rate First
Base-rate neglect is the tendency to underweight or ignore prior probabilities (how often things happen in general) when vivid, specific information is available. Identified by Kahneman and Tversky, it is one of the most robustly replicated biases in judgment research, and it leads to systematic overconfidence in predictions about specific cases. Correcting it requires actively looking up or estimating base rates before evaluating individual information.
- Base Rate Neglect Why We Ignore The Odds When Starting Out
Base-rate neglect is the tendency to underweight or ignore prior probabilities (how often things happen in general) when vivid, specific information is available. Identified by Kahneman and Tversky, it is one of the most robustly replicated biases in judgment research, and it leads to systematic overconfidence in predictions about specific cases. Correcting it requires actively looking up or estimating base rates before evaluating individual information.
- Base Rate Reasoning
Base-rate neglect is the tendency to underweight or ignore prior probabilities (how often things happen in general) when vivid, specific information is available. Identified by Kahneman and Tversky, it is one of the most robustly replicated biases in judgment research, and it leads to systematic overconfidence in predictions about specific cases. Correcting it requires actively looking up or estimating base rates before evaluating individual information.
- Failure Base Rate
Base-rate neglect is the tendency to underweight or ignore prior probabilities (how often things happen in general) when vivid, specific information is available. Identified by Kahneman and Tversky, it is one of the most robustly replicated biases in judgment research, and it leads to systematic overconfidence in predictions about specific cases. Correcting it requires actively looking up or estimating base rates before evaluating individual information.
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