class balance
How evenly the examples are spread across the classes.
Class balance describes the distribution of examples over classes; under heavy imbalance, overall accuracy can be high while a rare class is never detected.
Examples
With 1,000 idle windows and 50 taps, a model that always answers idle scores 95.2 % yet never finds a tap.
The lab records 400 windows of each gesture so no class dominates.
See also