Holacracy Community of Practice Archive, 2015-2019 Community Holacracy Web Site

You are correct.  The lead link has the explicit accountability of defining metrics for the circle.

So, the steps are as follows:

1.  Role created using IDM process in Governance, or asynchronous Governance process 

2.  Lead Link  assigns a role-filler to the role

3.  Lead Link defines metrics for the circle and specifies which role is responsible for reporting the metric.

(Const. 4.1.1 - Duty of Transparency) Role-fillers must also track and report on any metrics assigned to your Roles by the Circle’s Lead Link, or by any other Role or process granted the authority to define the Circle’s metrics.