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

ABSTRACT

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.

KEYWORDS:

• Default option
• green nudge
• natural experiment
• nudge
• waste management

JEL CODES:

• D91
• Q56
• Q58

Disclosure statement

No potential conflict of interest was reported by the author(s).

Notes

1 Groningen, Rotterdam, Utrecht, Breda, Tilburg, Zoetermeer, The Hague and Arnhem function as the control group. Eleven of the 20 largest municipalities did not have sufficient data on paper waste to be included.

2 The representative of the municipality of Groningen mentioned that paper waste in Groningen in 2018 was wrongly measured due to a miscommunication between the municipality and the waste disposal company. The miscommunication is exogenous to the paper waste in Groningen and is, therefore, also random. A sensitivity test in Table 1 concluded that the missingness of outcomes is random and does not bias the estimates.

3 Correlation coefficient larger than 0.8 (Franke 2010). See Appendix III.

4 Rotterdam, The Hague and Utrecht are included as control group, as they show similar paper waste levels prior to the implementation of the green waste nudge in Amsterdam (Figure A1 in Appendix I).

5 For example, when a household receives 100 kg of paper waste. 75 kg would be recycled and, therefore, measured. 30% to 50% of all paper waste is unaddressed mail, which implies 22.5 to 37.5 kg of unaddressed mail. Due to the default nudge 41.2 percentage points fewer households received unaddressed mail, which would imply an average paper waste reduction between 9.27 and 15.45 kg. Our estimates of a 5.3% to 11% reduction overlap with this range.

Additional information

Funding

This work was supported by the REACHOUT project. The REACHOUT project has received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement No 101036599.