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. 2020 Dec 8;6:36. doi: 10.1038/s41531-020-00135-w

Fig. 2. Primary outcome (any-rater criterion).

Fig. 2

The mean leave-one-subject-out cross-validation (LOSO-CV) classification accuracy of the smartphone-based prediction of the blinded MDS-UPDRS III. The accuracy of a number of approaches is compared to a random baseline (similar to rolling a dice where subjects were randomly assigned to a clinical category). The fully pre-specified analysis (blue) relied on pre-published features and a standard multinomial regression model. The Best Classifier approach selected the best classifier from a range based on best performance but used only the pre-specified features. The Best Feature approach selected the best feature from a range but used only the pre-specified classifier. The Best Classifier and Feature approach selected the best combination of both. Approaches are graded according to the risk of selection bias: the pre-specified analysis has a very low risk, the Best Classifier or Best Feature analyses have low risk whilst the combination approach has a moderate risk of over-optimistic accuracy. Error bars represent SEM.