It may seem surprising that models with more informative hybrid features did not strongly outperform those with OHE. However, since the latter already allows for a qualitatively good performance, there is little room for improvement when using more descriptive features. As discussed, with a random partition for the training/testing data it is likely that every ligand will be represented in the training data and, as such, it is likely that the good performance of OHE results from this 'data leakage' since the other two parameters (boronate, pre-catalyst)