Yes. We have Holacracy roles for each circle, who is accountable for monitoring the engagement in each circle (we call them Engagement Ambassadors).
The objective is simply to reach highest possible engagement, and to be able to know how we performance/improve on a weekly/bi-weekly basis, so we can react quickly, rather than e.g. only having quarterly/annual surveys.
In addition, we wanted to distribute the accountability for Engagement to each circle. Each role holder in the circles are informed weekly via email how their circle is performing, and all Engagement Ambassadors across all circle also meet on a regular basis to exchange best practices on how to improve engagement in their circles.