Fig. 4.

Overview of the analysis of simulated data for each experiment. After an external hold-out, we computed the performance of a site prediction classifier trained using (a) the harmonizer transformer within the machine learning pipeline (internal not leaked test set) and (b) harmonizing all data with neuroHarmonize before imaging site/age prediction (internal leaked test set). Secondly, we compared these performances with that observed on an external test set never used for harmonization and training.