Test set
A subset of the dataset reserved for testing a trained model. Traditionally, you divide examples in the dataset into the following three distinct subsets:1
- a training set
- a validation set
- a test set
Each example in a dataset should belong to only one of the preceding subsets. For instance, a single example shouldn’t belong to both the training set and the test set.1
The training set and validation set are both closely tied to training a model. Because the test set is only indirectly associated with training, test loss is a less biased, higher quality metric than training loss or validation loss.1