validation set

The subset of the dataset that performs initial evaluation against a trained model. Typically, you evaluate the trained model against the validation set several times before evaluating the model against the test set. Traditionally, you divide the examples in the dataset into the following three distinct subsets: - a training set - a validation set - a test set Ideally, each example in the dataset should belong to only one of the preceding subsets. For example, a single example shouldn't belong to both the training set and the validation set. See Datasets: Dividing the original dataset in Machine Learning Crash Course for more information.

Practitioners refer to validation set when building, training, or evaluating machine learning systems. It appears in research papers, product documentation, and technical discussions about AI capabilities and limitations.