The Municipality of Dordrecht organised a competition titled The Cleanest Neighbourhood in Dordrecht. The aim was to get residents to place less rubbish next to underground waste containers. As a result of the experiment, the amount of waste left next to bins decreased and a new social norm was established.

Why this experiment was conducted: rubbish left next to waste containers
Bin liners and other bags containing residual and larger waste left next to underground containers rank amongst the greatest causes of annoyance to residents. The sight of rubbish on the ground often invites even more waste. In Dordrecht, 'crash trucks' drive past the waste containers every other day to clean up any added rubbish, but even that is not enough. The Municipality therefore resolved to break the social norm: people should consider it less normal to leave rubbish next to underground containers.

Type of intervention: The Cleanest Neighbourhood in Dordrecht
The Municipality teamed up with a behavioural consultancy to devise a competition. Over a period of eight weeks, five neighbourhoods competed for the title of cleanest neighbourhood in Dordrecht. The neighbourhood with the most number of days without any bin liners or bulky waste dumped next to underground containers was the winner. The central objective of the intervention is to break routine behaviours and the social norm, thereby reinforcing residents' intrinsic motivation directed towards a clean neighbourhood. A waste counter was placed next to the container that kept track of the number of days without dumped waste. This ensured the behaviour was made visible to the public, thereby providing daily feedback on the amount of rubbish left next to the container. A long period without any waste left next to the container reinforces the social norm that most people do not dump rubbish next to bins.

Method used: baseline and impact measurements and perception survey
A baseline measurement was performed over a period of two weeks to keep count of the amount of waste left next to bins. The same count was kept during an impact measurement that was performed over the course of the eight weeks that the waste counters were placed next to the containers. A score was calculated to quantify the degree of seriousness in waste dumping: for example, five bin liners left next to the waste container on one occasion is less serious than a single bin liner left next to the container for five days. Also, in a perception survey residents were asked about the impact of the competition, such as whether the neighbourhood is cleaner and whether they are now committed to doing more to keep it that way. This was performed in door-to-door surveys (N=148).

Result obtained: reduction in the amount of waste left next to bins
The competition had a positive impact. Compared to the baseline measurement, the waste dumping score decreased significantly in the first four weeks in all neighbourhoods. This score remained low in neighbourhoods where little waste was left next to containers during the same weeks. A new social norm was established there. The perception survey showed that residents of these neighbourhoods also perceived their neighbourhood as cleaner. They indicated that they are now committed to doing more to keep their neighbourhood clean. This confirmed the new social norm.

Impact: liveable neighbourhoods and recycling
The Cleanest Neighbourhood in Dordrecht has reinforced the right social norm for disposing of waste. This improves both the living conditions and quality of life as well as sustainability in a neighbourhood. By placing less waste next to underground containers, local residents prevent liter and stench that attract vermin. Moreover, waste they dispose of properly can be used as raw material for compost, recycled plastic and paper, glassware and much more. The response from local media has been enthusiastic.

Source: https://www.binnl.nl/home+-+en/knowledge/publications/bin+nl+publications/HandlerDownloadFiles.ashx?idnv=2719979