We performed a parameter analysis to investigate the influence of certain OpenFF parameters on the errors. For each perturbation, the force field parameters involved in the perturbations were identified, i.e. only parameters which are either changed or annihilated during the perturbation. For each parameter, the RMSE across all perturbations involving this parameter was calculated. As parameters are often used in the same combination (e.g. the bond, angle, and torsion parameters describing an ester group), the correlation between parameters used in the same edges was calculated using the Matthew's correlation coefficient as it is suited to correlate binary vectors (parameter either used or not used in edges). The obtained cor-relation matrix between parameters was then clustered with spectral clustering 69 to identify groups of parameters which are used simultaneously in perturbations. To analyze the influence of a parameter change from OpenFF-1.0 to OpenFF-2.0 on the prediction error, the ∆RMSE of parameter p was calculated as