Tuning data

Tuning data helps choose architecture and settings, so data used this way can no longer serve as independent test data. It corresponds to what the EU AI Act calls validation data, which is easy to confuse with design validation.

These data are typically used by the manufacturer of an AI-DSF to evaluate a small number of trained AI models. This process involves exploring various aspects, including different architectures or hyperparameters. The tuning phase happens before the testing phase of the AI-DSF and is part of the training process. While the AI and ML communities sometimes use the term “validation” to refer to the tuning data and phase, FDA does not use the word “validation” in this context.

FDA guidance: Marketing Submission Recommendations for a Predetermined Change Control Plan for Artificial Intelligence-Enabled Device Software Functions (August 2025), Section IV, Definitions