Street-level workers resist outcome metrics that omit controls for client difficulty

Evidence

Thus teachers resist being measured by the progress of their pupils unless adequate provision is made to control for their students’ previous levels of achievement (and, more important) for their students’ capacity to learn. Thus police officers would object to utilizing arrests per capita per available officer as measure of performance unless controls were introduced for the propensity of criminal behavior in the district. — Michael Lipsky, Street-Level Bureaucracy, 1220