The New York City Housing Authority (NYCHA) is the largest manager of public housing in North America and provides housing to 1 in 15 New Yorkers. One widespread and highly visible concern for residents is the improper disposal of household trash, litter, and dog waste on NYCHA grounds, affecting their quality of life. Residents complain that household trash left in hallways, staircases, and outside the main door of their building makes the areas smell bad and attracts rats. Development caretakers share in their frustration, reporting they are often unable to complete all their work duties because of the time spent clearing trash. Dog waste left on NYCHA property is consistently reported across developments, on sidewalks, in the grassy areas, and even indoors.

A behavioral diagnosis conducted through site visits and interviews with NYCHA residents and staff revealed a number of insights on contributors to the trash problem. For one, NYCHA policy and infrastructure makes it very difficult for residents to throw out trash correctly. While dated trash compactor chutes on floors can accommodate trash bags from small wastebaskets, and large, bulky items can be taken to drop sites often several blocks away, residents are left without a practical and convenient option for disposing the most common size of trash bags used in tall kitchen trash cans. In the absence of policy or infrastructure solutions, residents have developed their own norms for trash disposal, following the cues of others to leave trash bags in easily accessible locations, such as the front and side of buildings, despite signs explicitly prohibiting trash disposal there. NYCHA staff clean up from these locations, sending mixed signals to residents and suggesting these locations are in fact acceptable drop areas. Even a small amount of visible trash is salient, and feeds misperceptions about normal resident behavior that promote improper trash disposal. Finally, frequently posted threats of punishment or fines may undermine intrinsic ethical motivations, and routinely unenforced fines can exacerbate problematic behaviors like not cleaning up dog waste.

A 2-part intervention was designed in consultation with NYCHA staff and residents to reduce the burdens associated with trash disposal in public housing.

1) Installation of large, moveable trash containers (tilt trucks) and trash cans in convenient locations at the front and/or side of buildings helped with the primary problem related to trash waste – the difficulty residents face to correctly dispose of household trash that does not fit in the trash chutes. Providing a clear location for disposal of trash gives residents an alternative to depositing trash in informal drop sites near their apartment buildings. Additional trash cans were placed around development grounds to facilitate disposing of dog waste and litter.

2) A package of posters informed people of the new policy and encouraged them to use the new infrastructure. These posters gave NYCHA residents guidance for disposing different types of trash, reminded dog walkers to bring pick-up bags, and discussed unpleasant effects resulting from improper disposal. Previous communications had only told residents what not to do, with the desired behavior often unspecified (people were told not to put trash bags in specific locations, but not told where to put them). The new signs gave guidance about what residents should do, recognizing that people were often motivated to take care of their environment.

Intervention sites received 1-2 tilt trucks per residential building, 2-3 trashcans per residential building, and the full suite of posters (6 inside versions for lobbies and floors and 3 outside versions) to provide significant coverage to reach all residents in the development.

A team of research assistants was trained to count individual trash bags, pieces of litter, and instances of dog waste visible during weekly site visits to all intervention sites as well as control sites over a four month period covering before and after intervention roll-out.

A randomized evaluation found that providing easier access to trash disposal infrastructure, complemented by community-oriented and instructional communications, significantly reduced the amount of trash visible on NYCHA grounds. Monitoring revealed significant (p<.05) decreases in the average number of trash bags (by 25%), litter (by 16%), and dog waste (by 11%) observed on development sites after rollout of the intervention materials, compared to baseline and relative to sites without the intervention.

Although the intervention was only installed for up to 10 weeks on treatment sites, we did not find that additional weeks of exposure were associated with a significantly greater, or smaller, reduction in trash and litter observed, which suggests a potentially consistent and lasting effect of the intervention.

This intervention had the strongest unadjusted effects compared to control on sites in the third quartile of baseline distributions for trash and litter, but was least successful on sites in the fourth quartile (figures below). Developments that were dirtier than average, but not the dirtiest, were the most impacted, supporting the conclusion that basic resource provision may be sufficient to have impact on sites with significant trash problems, yet more tailored, robust infrastructure upgrades may be required to show impact on sites with varied baseline levels.

Inspired to implement this design in your own work? Here are some things to think about before you get started:

• Are the behavioral drivers to the problem you are trying to solve similar to the ones described in the challenge section of this project?
• Is it feasible to adapt the design to address your problem?
• Could there be structural barriers at play that might keep the design from having the desired effect?
• Finally, we encourage you to make sure you monitor, test and take steps to iterate on designs often when either adapting them to a new context or scaling up to make sure they’re effective.

Additionally, consider the following insights from the design’s researchers:

• Posters were user tested with residents and were intentionally designed to look different from other NYCHA communications, stand out amongst other signs and notices, include a balance of visuals and text, take a more personal and respectful tone to contrast the standard tone typically perceived as bureaucratic and harsh, and emphasize community.
• Property managers for each NYCHA development in the intervention group were given recommendations on where to place intervention materials within and around residential buildings but were ultimately given discretion on which of the materials were installed, when, and where. Developments were asked to install all tilt trucks, trashcans, and posters starting the same week; however, delays in procurement and varied installation efforts by staff resulted in a much more gradual roll-out across sites. It took several weeks, and follow-up reminders from NYCHA, for the majority of treatment sites to rollout the intervention. NYCHA provided locks and chains to secure the trash cans and tilt trucks in place.
• Implement permanent, sustainable, and structural solutions. This infrastructure intervention was ultimately a compromise due to challenges in implementing a more desirable infrastructure change – enlarging the openings of trash chutes within NYCHA buildings, which would allow residents to dispose of larger items such as the common 13-gallon trash bags used by many households.
• Prioritize convenience for residents and provide consistent access. Place trashcans in convenient and accessible locations to ensure that residents use them regularly. Ensure that resources are available to residents consistently and that each site has adequate resources and support for successful implementation.
• Ensure adequate support at higher-need sites – some sites and residents require a higher level of care or an adapted solution set. For example, we heard that seniors may have had trouble utilizing the tilt trucks because lids were too heavy. In senior only buildings, address their mobility issues with additional trash collection services, or make disposal locations and structures more convenient.
• Draw on residents’ sense of community to motivate behavior – residents are eager for upgraded resources and infrastructure, but also appreciate the sense of community they find at NYCHA developments.
• Consider last mile efforts – while changing resident behavior is an important angle, monitor staff behavior for any unintended consequences that interventions may be having.