A default nudge in waste management: assessing the impact of explicit consent for unaddressed mail

On 1 January 2018, the municipality of Amsterdam changed the system for the reception of unaddressed mail from presumed consent to explicit consent to reduce paper waste. This policy can be defined as a default nudge. The no-choice population received unaddressed mail in the presumed consent system but not in the new explicit consent system. Residents receive unaddressed mail only when they actively decide to put an opt-in sticker on their mailbox. This study assesses the effectiveness and social benefits of this nudge. The effect on paper waste is estimated using a difference-in-differences approach in which several other Dutch municipalities function as the control group. Our main finding is that the default nudge results in a reduction of paper waste between 5.3% and 11%. Social benefits of this reduction include, for example, lower carbon emissions for collection and transport for paper waste, which are equivalent to yearly benefits between approximately €135,000 and €285,000 in Amsterdam. If all Dutch municipalities implement the system of explicit consent for unaddressed mail, the yearly benefits are approximately between €14 million and €30 million. The default nudge is a low-cost policy to implement and, therefore, offers municipal policymakers a cost-effective way to reduce waste.