The 86% Who Agree but Do Not Segregate
A municipal solid-waste team finds that only 38% of households in a 400-flat complex segregate waste correctly, although a survey shows 86% agree that segregation is 'important'. The complex has 8 floors of 50 flats; the ground-floor bins are shared. The team has a small budget and three options: (a) print a leaflet explaining the rules; (b) display each floor's correct-segregation rate in the lobby; (c) ask households to sign a public commitment card. A previous leaflet campaign raised awareness but not behaviour. Residents say the bins are confusing and that 'everyone else mixes waste anyway'. The team wants a 12-week campaign and will measure bin contamination on four unannounced days before and after. The team can afford only one option at full scale, or two at half scale.
1. Explain the attitude–behaviour gap and why the leaflet campaign failed.
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The 86%–38% gap is an attitude–behaviour gap: a general evaluative statement that segregation is important is not the same as a specific behavioural intention under situational constraints. The leaflet raised awareness and knowledge but did not change the immediate cues, effort or social norms at the bin. Attitudes predict behaviour better when they are specific, accessible, formed through direct experience, and when perceived behavioural control and subjective norms support the act. Residents report confusing bins, which lowers perceived control, and 'everyone else mixes', which is a descriptive norm favouring inaction. The leaflet addressed the wrong barrier.
2. Choose among the three options using social norms, commitment and cognitive dissonance, and justify your choice.
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Option (b), floor-level feedback, is likely strongest because it makes the descriptive norm visible and comparative, and it is specific and close to the behaviour. However, a displayed rate of only 38% can backfire, so show each floor's own trend and an achievable comparison, and pair it with an injunctive message such as 'this floor is expected to segregate'. Option (c), public commitment, can work through consistency and cognitive dissonance, especially if residents make a small specific pledge and receive a follow-up, but signing may attract only already-motivated households. Option (a) alone is weakest. A feasible choice is commitment cards on floors 1–4 plus feedback on all floors if the design permits comparison. If only one option is possible, choose floor feedback with a positive norm and specific 'how' instructions.
3. Design the evaluation and identify one confound and one ethical issue.
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Use four unannounced pre-campaign contamination audits and four post-campaign audits, on the same days of the week, with blinded raters and the same bin sites. The unit is the floor or household cluster. Randomise floors to condition if possible, or use a stepped-wedge design. One confound is a city-wide waste campaign or a holiday period coinciding with the intervention; record contemporaneous events and use a comparison complex. Measure contamination objectively by weight or photograph, not by self-report. One ethical issue is that publicly displaying a floor's poor performance could stigmatise residents; use aggregated, non-identifying feedback, obtain consent, and avoid shaming. Also ensure the bins are genuinely available and accessible, otherwise the intervention is unfair.