This article from February 2014 has some insight and advice that will help you decide the best way to measure your impact. You don’t have to be a big, national charity to give these issues some thought, in fact there are a range of ways that even the smallest groups can incorporate measuring changes into their work.
The article was written by Tris Lumley and James Noble who work at NPC and was published by the Guardian Voluntary Sector Network. It introduces the basic questions you will need to answer in order to start measuring your impact.
Source: Guardian Voluntary Sector Network