How do I identify three to five key metrics for a specific nonprofit or public/

How do I identify three to five key metrics for a specific nonprofit or public/government organization that will give a leader enough information to manage performance, grow the outreach of the organization, and help to establish evidence to develop or support a current policy for positive social change.
Post three to five key metrics for a specific nonprofit or public/government organization that will give a leader enough information to manage performance, grow the outreach of the organization and help to establish evidence to develop or support a current policy for positive social change. Be sure to validate with two peer-reviewed, scholarly resource(s). 
Organization:
Tri-Counties Regional Center.         https://www.tri-counties.org/
Scholarly Articles:
https://www.prosci.com/blog/metrics-for-measuring-change-management
https://journals.sagepub.com/doi/full/10.1177/18479790211016273