“…An exhaustive and detailed validation was undertaken to gauge the efficacy of the proposed composite clinical motor score in providing a comprehensive overview of motor symptoms, by comparing it with the MDS-UPDRS III based on the following seven criteria: (1) discrimination accuracy : the ability to distinguish between the disease groups (controls, iRBD and PD), whereby the accuracy was quantified using AUC values; (2) consistency : using the coefficient of variation (SD/mean) as an indicator of overall variability relative to the mean33 34 and using the weighted mean absolute percentage change (for control participants who underwent baseline and repeat in-person assessments: defined as the sum of each participant’s absolute change in score between baseline and repeat assessments/the sum of all baseline scores, with the value expressed as a percentage), a measure akin to the weighted mean absolute percentage error (wMAPE),35 which allows the quantification of forecasting errors relative to a ground truth, bypassing errors that would arise with baseline values of 0, were the mean absolute percentage change to be calculated; (3) correlation : measuring Spearman’s correlation with other clinical measures; (4) sensitivity to disease stage : change in the score values for different stages of disease severity (as assessed via the H&Y stage); (5) longitudinal progression : ability to track disease progression over time, for all participants with iRBD and PD—additionally, for participants with PD, the longitudinal standardised score trajectories according to baseline cluster (PD cluster 1: fast motor progression with symmetrical motor disease, poor olfaction, cognition and postural hypotension; PD cluster 2: mild motor and non-motor disease with intermediate motor progression; PD cluster 3: severe motor disease, poor psychological well-being and poor sleep with an intermediate motor progression; PD cluster 4: slow motor progression with tremor-dominant, unilateral disease), as previously described, were also compared to determine whether the trajectories were preserved across scores36; (6) relative linearity : as calculated by the wMAPE (the sum of the absolute difference between the true and predicted scores, divided by the sum of the true scores) of individualised linear predictions based on two or more composite clinical motor scores from the same individual at discrete time points being used to predict their composite clinical motor scores at other time points; and (7) prediction accuracy : ability to predict clinical outcomes, quantified using AUC values, in PD including (a) falls (at least one self-reported fall in the preceding 6 months), (b) freezing (a frequency of freezing other than ‘never’; ie, a score of at least 1 in answer to the question ‘Do you feel that your feet get glued to the floor while walking, making a turn or when trying to initiate walking (freezing)?’ on the Freezing of Gait Questionnaire), (c) cognitive impairment (a score of 1 or more on MDS-UPDRS I item 1.1), and (d) problems with self-care and performing usual activities (a score of >1 on each EQ-5D-3L item, denoting the presence of at least some problems).…”