Fig. 4

Variable importance plot for the six models built with different input datasets and tuning parameters. Variable importance here is computed using the mean change in the Gini index (x-axis), and is expressed relative to the maximum. The shape represents the algorithm used and color represents the size of the input dataset. The small data set that includes UL clinical measures, the medium sized data set includes UL clinical measures + non-motor clinical measures, and the large sized data set includes UL clinical measures + non-motor clinical measures + demographics. The bagged models were built with all predictors available in the data set and random forests were built with the square root of the number of predictors