There is a saying, "you cannot manage what you do not measure." Measurement works because a management team naturally pays attention to that which is being measured. A nonprofit is then very capable of improving what it focuses on and aligns resources around.
Many organizations are unable to improve because they are unfocused or are pulled in many directions; focusing on critical activities is the key. Furthermore, no organization wants to think of itself as average or below average. When a nonprofit knows measurably how it stands vis-à-vis its peers (especially those performing at levels of excellence), a natural sense of friendly competition where everyone can win is invoked.
A nonprofit that is falling far short of excellence will be motivated to improve by learning from consultants and other nonprofits at the top of its peer group; the nonprofit will also be able to mark and show donors its quantitative progress toward measurable excellence. Meanwhile, top performing nonprofits not only help other nonprofits emulate their success, but they are also motivated to keep setting the standards of excellence even higher. Most importantly from the fundraising perspective, a nonprofit has an instant report card that it can show its donors (noting both areas of excellence and areas for improvement). Finally, if a networked nonprofit is to invest in a consulting team for help, it must be equipped with tools allowing it to challenge and motivate each nonprofit affiliate.