Whether due to ideological commitments, grants, a deficient view of "science," puffing up their own worth, lack of imagination, or simple laziness (my top nominee), the obsession with measuring is the technocrat’s path to legitimacy, particularly in holding authority. In general, the less actual authority they have the more they will trust numbers to do their work for them. They trust numbers because they don’t trust their colleagues.

As Theodore Porter argued in his wonderful Trust in Numbers, quantification is a historically-emergent "social technology" that not only gains currency during periods of political centralization and the development of large-scale economic organizations, but transforms (indeed, even creates) the social sphere itself.

The key impulse, he demonstrates, arises from a "technology of distance."

In other words, distance creates a certain amount of distrust since local customs, actors, and practices no longer exercise their own authority. As authority becomes more centralized, it also becomes more regularized and more concerned about the problem of "subjectivity," that is, the variations and difficulties associated with individual judgments or local idiosyncrasies ...

Large-scale philanthropy’s use of metrics reveals their trust of numbers and distrust of humans.

Granted, humans disappoint and make mistakes, but numbers are not the neutral instruments the technocrats like to think they are and often result in a further dehumanization of the social sphere.

Read the full article about the problem with "measurable impact" by Jeff Polet at Philanthropy Daily.