Return the balance of perception between the two nodes.
        A positive score indicates the result is relatively better for active.

def _relative_score(self, start_eot, end_eot, active, passive):
        """Return the balance of perception between the two nodes.
        A positive score indicates the result is relatively better for active.
        """
        active_start = self._score_eot_for_actor(start_eot, active)
        passive_start = self._score_eot_for_actor(start_eot, passive)
        active_end = self._score_eot_for_actor(end_eot, active)
        passive_end = self._score_eot_for_actor(end_eot, passive)
        return (active_end - passive_end) - (active_start - passive_start)