Fig. 5From: Predicting medical usage rate at mass gathering events in Belgium: development and validation of a nonlinear multivariable regression modelValidation of the multivariable PPR prediction model. a Temporal validation of regression tree, adjusted for Tmax, with the 2018 dataset. b External validation of regression tree, adjusted for Tmax, with other 2009–2016 manifestations. The solid red line represents a perfect match between the observed and predicted PPR; the dotted red lines indicate 25% under- or overestimationBack to article page