Purity versus completeness for the selection based on different thresholds for each class From top to bottom, the panels show the galaxy, QSO, and star class. The curves represent purity (blue) and completeness (red) of the sample as functions of the chosen threshold and percentile used to select the class. Vertical dashed lines in corresponding colors indicate the probability thresholds required to achieve 99% purity (blue) and 99% completeness (red), respectively.