Waste disposal at undesignated sites in public open spaces causes hygiene problems, city landscape deterioration, and urban flooding in many developing countries. The researchers used different types of norms—subjective norms, perception about government pressure as one injunctive norm, and personal norms—as interventions to promote people’s intentions to avoid disposing of waste in public open spaces. Six different statements focusing on these three norms were designed, and the residents’ tendencies to follow each statement were investigated using 15 pair-wise comparisons in Phnom Penh, Cambodia. In addition, the likely effectiveness of each statement to encourage the residents’ intentions was asked of national and local government officials using the same pair-wise questions.
