Probability Bucket
A probability bucket is a range of predicted probabilities used to group forecasts for calibration analysis, such as 0.60 to 0.70.
Definition
A probability bucket is a bin, or range, used to group probability forecasts for analysis. Buckets are used most often to evaluate calibration.
Typical bucket choices
• 10 buckets of width 0.10 (0.00 to 0.10, 0.10 to 0.20, and so on).
• 20 buckets of width 0.05 for more detail when you have enough data.
Tradeoffs
• More buckets gives a more detailed picture but needs more forecasts per bucket.
• Fewer buckets is more stable on small samples but hides fine grained issues.
Why it matters
Scorecards often report per bucket stats like count, average predicted probability, and realized frequency. These bucket summaries power calibration curves and reliability diagrams.