Evaluating microscopic pK a predictions was limited by the availability of experimental results. For the seven molecules with NMR supported microscopic pK a s, our predicted values agreed with experiment within predicted uncertainty. This was a rather limited set of the possible microscopic transitions so we also compared our performance to top-performing commercial products. For microscopic predictions with low predicted uncertainties, our model performs well compared to Simu-lationPlus and ACD Labs commercial products (Figure ). While these results are promising, this portion is a comparison of three predictive models and has not been experimentally verified. A valuable addition to future SAMPL challenges including pK a predictions would be to expand experimental measurements to include more microscopic results when available.