We are often more certain than the evidence really allows.
More quotesInstall a recycling bin beside the sinks. Watch paper towel use rise by half a towel more on average. Admire the bin filling with evidence that the intervention is working. This is how good intentions mug outcomes.
Recycling lowered the felt cost of using another towel. The extra sheet seemed less wasteful because it would enter the virtuous container. Across one busy washroom, that tiny permission became roughly 12,500 additional towels a year. Nothing in the sign requested higher consumption; behaviour found the invitation anyway.
Rebound effects turn up wherever an improvement changes the price, effort or moral meaning of an action. Efficient lights feel safer to leave on. Free returns encourage ordering six sizes. Faster roads attract journeys until traffic eats the saving. The solution works locally and the system responds globally. Recycling and efficiency survive this evidence. Lazy measurement should not. A rising recycling rate can coexist with rising waste, just as more use of an efficient device can erase some of its promised saving. Participation is seductive because it is immediate, visible and flattering to whoever launched the scheme.
Now imagine two photographs in the evaluation report. One shows the empty recycling bin before the programme. The other shows it overflowing afterwards. The intervention looks magnificent until somebody places annual towel consumption underneath. Policy met human permission: another sheet had become easier to excuse. The awkward result was sitting in plain sight, waiting for someone to measure the rubbish instead of admiring the bin.