Finally, the approach to dealing with rare values is investigated. The reaction string datasets would have more than 10,000 unique agents (see Table ) with no frequency based filtering, which would create a sparse OHE. We initially hypothesized that the rare ! "other" strategy would allow for better generalisation, since the edge case reactions would be kept in a way that also keeps the OHE at a reasonable size. However, in practice, the rare ! delete rxn strategy had better performance across train set sizes, as seen in Figure .