As noted in this post, our regional group of regulators and municipal stormwater permittees is moving away from quantifying trash loads and trash reductions.
That’s a good thing, but we seem to be stuck with assessing success by documenting outputs (for example, frequency of street sweeping, or portion of the drainage system equipped with capture devices) as well as documenting outcomes (for example, less trash on streets or in creeks).
Documenting outcomes is hard, and results are uncertain. A municipal permittee could try like hell to clean up the trash but trash could still increase because of factors beyond its control (for example, a demographic change, or windier weather). Or vice versa: There could be less trash over time, but for reasons that have nothing to do with the local trash reduction program. A municipal permittee’s compliance shouldn’t be subject to vagaries.
But the assessment of success shouldn’t be about compliance. It should be about continuous improvement.
To solve a problem iteratively, you need to first guess a solution. Then you need a way to tell whether you are off, and in what direction. Measuring outcomes at least gives you a chance to figure out whether what works and what doesn’t. You might give yourself a bum steer (because of vagaries), but you can at least try to consider the context and make sense of the results. In contrast, measuring outputs shows that you tried, but there’s no way it can help make your efforts more effective.
