To establish whether inclusion of detailed information on assay context could be helpful for bioactivity prediction modeling, we compared bioactivity outcomes from different assays with overlapping protein-compound measurements (423,195 datapoints). Plots of pChEMBL values of proteincompound pairs that were measured repeatedly, show a large variability in measured pChEMBL values for the same target-compound combination (Figure ). The MAE for all repeated datapoints with an associated accession value is 0.83. For GPCRs, tyrosine kinases and SLCs this is 0.76, 1.16 and 0.54, respectively. To establish whether assay context explains part of this variance, the average of the MAE within assay clusters derived from the best performing clustering approach was calculated. Overall,