It's worth briefly speculating as to why GDCC binding affinity predictions may be more accurate than those for CB8. We speculate that methods achieve greater predictive power for GDCC systems because the guests are typically more rigid and "simpler" as opposed to guests in the cucurbituril datasets in this challenge, though also the availability of empirical data from prior CB8 studies may be helpful to tune methods (as indeed several methods using empirical corrections saw improved performance here). Sampling of water displacement and rearrangement has been reported to be a separate issue as well, or possibly the origin of problems in CB8. The binding of guests to CB8 also involves water displacement, but it is possible that additional complications not explicitly accounted for (ie. pKa shifts, protonation state modulation) contribute to the larger error in predictions.