Do Recycling Habits and Skills Disappear When Programs Are Paused?

This study investigates whether recycling habits and skills degrade after a temporary pause in recycling services. The authors analyze data from a natural experiment in New York City, where glass and plastic recycling were suspended from 2002 to 2004. Using a difference-in-differences and synthetic DID approach with control data from Massachusetts and New Jersey (1997–2008), they estimate that recycling rates declined by 6.5, 9.7, and 3.1 percentage points during the pause, but fully recovered by 2005. These results suggest that recycling habits and skills are persistent in the short term, and temporary interruptions do not cause lasting behavioral decline.

Full Citation and Link to Article

Brewer, D., & Cameron, S. (2025). Habit and skill retention in recycling. Journal of Policy Analysis and Management, 44(2), 533–552. https://doi.org/10.1002/pam.22554

Extended Summary

Central Research Question

The central question of this study is whether recycling habits and skills deteriorate when municipal recycling programs are temporarily paused. Specifically, the paper examines whether New York City residents’ recycling behaviors, formed under a mandatory recycling regime since 1989, weakened following an exogenous suspension of glass and plastic recycling collection between July 2002 and April 2004 due to budgetary constraints. The authors seek to determine whether these behaviors recovered after service resumed, thereby evaluating the persistence of recycling-related habits and skills among households and municipal service providers.

Previous Literature

Prior research on habit formation and learning-by-doing highlights that repeated behavior can lead to persistent actions even after an intervention ends. Much of this literature, however, evaluates outcomes after an intervention and rarely observes what happens when the intervention is paused and then resumed. Studies of health-related behaviors like diet and exercise (e.g., Harris and Kessler, 2019) and environmental behaviors (Allcott and Rogers, 2014) suggest that reinforcement plays a key role in habit persistence. Some interventions, such as price-based nudges for energy conservation, lead to longer-lasting effects than others. Within recycling, prior studies (e.g., Ouellette and Wood, 1998; Knussen and Yule, 2008) indicate that habit strength, frequency of past behaviors, and environmental context are predictors of sustained behavior, but few have examined causal effects from a natural experiment.

This paper contributes to both the economics and psychology of recycling behavior by using causal inference methods to evaluate a pause in recycling services. Unlike prior work focused on attitudinal surveys or interventions, the authors uniquely capture behavior before, during, and after the disruption. The study fills a gap in the recycling literature, which has historically emphasized factors like per-unit pricing, stated preferences, or demographic predictors rather than habit formation and decay due to policy interruptions.

Data

The study leverages administrative data from the New York City Department of Sanitation (DSNY), documenting monthly residential waste and recycling collection across boroughs from 1997 to 2008. The authors focus on the Bronx, Brooklyn, and Queens, as paper recycling data were missing for Manhattan and Staten Island during key years. The recycling rate is calculated as the share of total residential waste diverted through recycling (metal, glass, plastic, paper, and organics).

For comparison, control data were collected from 186 Massachusetts municipalities and 21 New Jersey counties over the same period. These states were selected for their large urban centers, demographic similarity, and availability of long-term recycling data. Recycling remained operational in all control jurisdictions, providing a counterfactual for evaluating New York City’s behavior during and after the recycling pause. Additional demographic and political data were used for covariate adjustments.

Methods

The primary empirical strategy involves a difference-in-differences (DID) research design, comparing recycling rate trends in New York City to those in control regions before, during, and after the pause. The main innovation lies in the use of a stacked synthetic difference-in-differences (synthetic DID) method, which creates weighted control groups that more closely mirror New York City’s pre-pause trends. This approach, developed by Arkhangelsky et al. (2021), allows for estimating time-disaggregated treatment effects while correcting for potential pre-trend imbalances that undermine traditional DID validity.

The authors generate yearly treatment effects for 2002 to 2008, using pre-treatment data (1997–2001) to construct weights. They further test robustness using joint (unstacked) synthetic DID, fractional-response models, and models with covariate adjustments. The quality of fit is assessed using Cohen’s d statistic, showing that the synthetic DID approach best matches the pre-pause trajectory of recycling rates.

Findings/Size Effects

During the recycling pause, New York City experienced a substantial drop in recycling rates. The synthetic DID estimates show reductions of 6.5 percentage points in 2002, 9.7 points in 2003, and 3.1 points in 2004. Given a pre-pause average recycling rate of 18.3%, the 2003 decline represented a drop of over 50%.

Remarkably, by 2005—the first full year after resumption—recycling rates had fully recovered. The synthetic DID estimate for 2005 shows a difference of just +0.06 percentage points compared to the counterfactual, effectively indicating no residual impact from the pause. From 2006 through 2008, recycling rates in New York City remained statistically indistinguishable from the synthetic control predictions, with treatment effects close to zero.

These findings suggest that the temporary disruption in service did not cause lasting behavioral decay. Instead, the evidence supports the persistence of recycling habits and skills. Additional analysis also showed dynamic persistence in recycling at the monthly level using Arellano-Bond models: higher recycling in one month predicted higher recycling the next, consistent with habit formation.

The authors also explored possible mechanisms behind the rebound. Enforcement of the mandatory recycling law did not appear to play a major role, as violation rates were low relative to population and declined over time. Financial incentives were also unlikely drivers, since New York City does not use per-unit waste pricing. Cultural attitudes toward recycling were strong but self-reported rates were likely inflated, and actual recycling levels were lower than in control jurisdictions. The authors argue that retention of complementary recycling behaviors (such as continued collection of paper and metal) and institutional readiness (e.g., quick rehiring of sanitation workers) helped preserve the infrastructure and behaviors necessary for recovery.

Conclusion

The study provides compelling evidence that recycling habits and skills are resilient to short-term disruptions. When New York City paused glass and plastic recycling for nearly two years, household recycling rates declined temporarily but recovered fully within a year of reinstatement. This finding counters concerns that temporary interruptions irreversibly degrade public recycling behavior or municipal capacity.

For policymakers, this result has practical implications. In periods of fiscal stress or when recycling markets collapse—as occurred after China’s 2017 import restrictions—municipalities might consider pausing recycling services without fear of long-term harm to behavioral norms. However, the authors caution that this does not imply a net social benefit to pausing recycling, since such decisions must also consider environmental externalities, costs of public communication, and the possibility of delayed market recovery.

The authors acknowledge limitations, including the unique context of New York City and the lack of data on contamination rates. Nonetheless, this is the first study to causally assess whether recycling behaviors persist through service suspensions, providing valuable insights into behavioral durability and policy flexibility in environmental management.