A model does well on the validation set but performs poorly on the final test set, and both sets come from the same process. What is the most likely diagnosis?

True or False: If validation and test data come from the same source, a large gap between validation and test scores always proves the model has too many layers.

The practical fix for overfitting the validation set is to gather more _____ examples.

Match each performance pattern to its best diagnosis

Order the steps for diagnosing a validation/holdout performance gap from the same data source

Why a Shared-Distribution Validation/Test Gap Signals Validation Overfitting

Diagnose a dev/test gap when both evaluation sets come from the same source

Why Dev and Test Sets Should Match

What is the practical fix when a model has fit the development set too closely?

A gap between validation and test performance always means you should add more test examples.