There are many ways to measure impact and value.  You will work with a coach to help you figure out the critical path measures of impact which will determine the success of your projects. These may vary hugely, ranging from number of particpants, re-tweets, gallons of water purified, meals provided to homeless, trees saved, etc., depending on the impact your project is designed to have.

This is one of the core skills that you'll learn in the Labs.