Tom Ricks posts some advice from David Kilcullen on various metrics that shouldn't be used when judging the success of war tactics. The quotes are Kilcullen; the rest is Rick's commentary:
"Any input metric [should be avoided]." Megadittoes. This was another thing that used to drive me nuts in Iraq, listening to Americans boast about money spent, projects initiated, patrols conducted, and such. "These indicators tell us what we are doing, but not the effect we are having." Rather, he advocates, look at outcomes, and especially the effect on the population.
How to look at outcomes here.