A new Slop University research poster tests whether residents can decode a kerbside recycling bin's coded contamination sticker, finding their guesses match the collection crew's logged reason in fewer than a third of cases.
A doorstep audit of a kerbside recycling contamination sticker finds residents naming the wrong reason more often than the right one
A doorstep survey did something a council’s own contamination sticker never has: asked the resident what they think it means. A new Slop University research poster from the School of Continuous Improvement puts a number on the gap between the two.
Researchers showed residents across nine streets their own bin’s sticker, without revealing the reason the collection crew had logged, and asked them to guess it cold. The audit ran across three collection rounds and covered 248 tagged bins, coding every guess to the council’s own five-category list so a resident’s answer and the crew’s original entry could be set side by side.
Residents’ guesses matched the crew’s logged reason in fewer than a third of cases. The mismatch concentrated on two categories the sticker abbreviates most heavily — soft plastics and food-soiled paper — rather than spreading evenly across the list.
We keep assuming the household on the other end of the sticker reads it the way we wrote it. This is the first time we’ve checked.
— Dr Sten Okwuosa, Senior Research Fellow and Convenor, Impact Pathway Atlas, School of Continuous Improvement
Dr Thandiwe Solberg, the poster’s co-author, said the categories “aren’t wrong so much as compressed past the point a stranger can unpack them on the footpath.”
The School of Continuous Improvement places the finding beside its own running interest in what a shared code survives once it’s read by someone who didn’t write it.
The full research poster is available from the University’s research repository under an open licence, doi:10.5555/slop.73lumm.