A confidence bound replaces a fragile point estimate with a limit that accounts for uncertainty. In model validation, it helps distinguish apparently strong offline metrics from performance likely to hold online. section 7.4
Coin toss intuition
After 100 fair-coin tosses, the number of heads is a point estimate. Saying that the result should fall between 40 and 60 in 95% of cases gives a confidence interval; 40 is the lower confidence bound. section 7.4
Use confidence bounds when validation decisions depend on uncertain metrics:
- Treat precision, recall, and similar metrics as distributions rather than single values. section 7.4
- Use bootstrap resampling for a stronger uncertainty estimate, while accounting for its substantial computational cost. section 7.4
