Nested Cross-Validation Calculator

Outer loop: Provides unbiased test error estimate
Inner loop: Selects best hyperparameters

Unbiased evaluation with hyperparameter selection

Data Values (comma-separated):

Outer Folds:

Inner Folds:

Nested CV provides unbiased performance estimates when hyperparameter tuning is involved.

Structure:

Why needed: Regular CV with tuning leads to optimistically biased estimates due to information leakage from test set into model selection.