Choose your favors carefully. If the message hasn't changed in two years, it's obsolete. You have to communicate through a variety of means to make your message stick. Evaluate the staff on the amount of feedback they receive. Now, the differentiating factors are leaders who can motivate more than the other side.
Grassroots measurement is more than just numbers.
The soft stuff is the hard stuff. If they haven't done it before, they can't do it for you. Act on what you hear and observe, not from what you believe or hope. Your volunteers will tell you how to keep them engaged if you pay attention. Find out what makes your active participants stay with your program and do more of it.