This is an ambition rather than a completed task as yet, because we are a new community, but the community is a place for members of a co-operative membership organisation that is in wine retail.
Our ultimate measure is “member satisfaction” with the overall Society, and the objective of the community is to add to the engagement between the Society and members, and between members with each other so that they are ultimately happier with their shared ownership.
In this case we will be evaluating their level of satisfaction through surveys, and I hope to demonstrate that the community is delivering BOTH overall increases in satisfaction (because more members are finding better wines and getting more from their membership) and that individual members who are participating in the community are more satisfied (their own satisfaction scores increase over time, and they are more satisfied compared to members who do not participate in the community).
There are other measures below this, regarding engagement with the community (inactive/reader/creator/moderator), and measures of revenue generated via referral traffic, but these are not as important as the higher level measure.
It is still early in the process as we have only just launched, but this is the goal we have set ourselves. Hope this helps