Although host-guest systems are "simpler", they still pose several additional modeling difficulties. For example, guests bearing a formal charge can be especially difficult to treat. Indeed, charged guests were shown to affect the accuracy of many methods in SAMPL7 . Polarization potentially plays a big role in predictive accuracy when modeling systems with charged molecules and in the presence of explicit water. A polarizable model used in the last two SAMPL iterations has outperformed all other methods in the datasets for which predictions were made. In SAMPL7 we observed that across all host-guest systems, methods using this polarizable force field approach provided additional accuracy but with an increase in computational cost due to the added complexity of the physical model to describe the systems. On the other hand, we have seen several methods using fixed charge force fields with performances comparable to the more expensive polarizable models. But these methods contain empirical corrections that rely on adjusting predictions for the particular target based on prior studies of that target . This would not be ideal for new datasets and in real world applications where there is little or no data available on a target.