conformers per a molecule -see Figure ), hence larger amounts of filtering result in reduced performance and are relatively insensitive to increasing the maximum allowed number of conformers. While increasing the number of conformers can only increase the recall of known actives, it can also reduce the precision (i.e., increase the number of false positives due to more inactive compounds matching the pharmacophore). This leads to a reduction in average performance as the maximum size of the ensemble is increased with minimal filtering.