In the SAMPL7 pK a challenge, participants predicted free energies for transitions between microstates. Predicted relative free energies were then converted to macroscopic pK a values in order to compare participants' predictions to experimental pK a values and calculate performance statistics of predictions. This format allowed us to avoid some of the challenges of matching microscopic transitions to macroscopic pK a values , making analysis more straightforward. As noted above, some matching is still required, but this approach eliminates uncertainty about which transitions are predicted.