What works?

Reducing contamination of household kerbside recycling

What works?

The placing of non-recyclable items ('contaminants') into household recycling bins is a persistent problem facing local, state and federal government waste policy makers, the waste industry and the community as a whole.

This project focuses on gaining a better understanding of why contamination happens in the first place and what behaviour change interventions can successfully help Australians improve their recycling practices.

Key activities

To understand (i) barriers to correct recycling, and (ii) potential interventions, we:

  1. Conducted interviews with policy stakeholders.
  2. Conducted a rapid evidence and practice review, investigating academic literature and practitioner experiences.
  3. Ran two co-design workshops with over 70 stakeholders to brainstorm, prioritise and select interventions to test.
  4. Designed a series of 3 field trials and 3 online experiments implemented by 23 local and state government partners.

In this video, Research Stream Leader, Jennifer Macklin (Downes), provides a concise summary of the research, what they did and what they found. For a more in depth summary, scroll down to Step 2 to download the Kerbside Recycling Summary Report.

Process and insights

In conducting this research, we followed the BehaviourWorks Method to gather evidence on the behaviour change approaches most likely to work.
(See a brief visual summary of the BehaviourWorks Method or a more extensive explanation.)

A step-by-step guide of how we followed The BehaviourWorks Method

Step 1 - Rapid Evidence & Practice Review


We conducted a rapid evidence review to summarise and evaluate published literature and practitioner reflections on the effectiveness of interventions for reducing contamination and encouraging correct recycling at a household level.

Alongside, we conducted a series of interviews with Australian policy-makers and reviewed their policy documents to better understand identified barriers and potential interventions in the Australian context.

In reviewing the literature, we found little high-quality evidence on 'what works' to change contamination behaviour. The review therefore focused on broader recycling and waste-related behaviour.

Note: BehaviourWorks Australia was engaged by the Australian Government Department of Agriculture, Water and the Environment to conduct this review, in parallel to the other work of the BWA Waste and Circular Economy Collaboration.

Key findings

The research revealed:

  • It is not easy for people to identify the 'right thing' to do, while contextual factors can also constrain cooperation.
  • Current recycling schemes are not necessarily designed to optimise correct recycling.
  • Interventions aiming to improve convenience and ease of preferred recycling behaviours are the most widely effective.
  • Effective communications need to be tailored to the specific characteristics of schemes, populations and preferred behaviours, and utilise social modelling/norms and persuasive messaging alongside information.

Download the Rapid Evidence & Practice Review

For readers wanting a quick overview of the evidence review (5 minute read):

2-page Summary of the review

For readers writing a brief, a policy submission or wanting a summary of practical insights:

Policy highlights of the review

For readers needing all the technical detail, including the full methodology:

Full report of the review

Step 2 - Co-design & Trials


These studies are based on a series of research activities that involve a review of the research currently available in academic literature, interviews with practitioners and policy-makers, and co-design workshops to synthesise and select trial ideas.

A total of 38 trials across three streams were initially planned, with 24 trial delivery partners across two states and all levels of government, coming together to co-design solutions. Despite the Covid-19 pandemic, 22 trials with 16 online experiments and 6 field trials, run in collaboration with 20 local councils, Planet Ark and our consortium partners, were able to be completed.

Our experiments and trials included:

Facebook online experiments: What works to grab and hold people's attention?

  • These experiments tested how different messages and images in social media advertisements could grab people's attention long enough to click through to a page for more information.
  • Specifically we tested messages and images to prompt clicks-through to learn more about either: soft plastic / bagged recycling contamination, or general recycling rules.

Online survey-based Flyer experiments: What works to improve people's sorting knowledge?

  • These experiments tested how different flyer designs, messaging, and images could increase people's knowledge and intentions on kerbside recycling streams and bins.
  • The aim was to improve the design of printed materials, such as flyers, to successfully educate the public on kerbside recycling.

Council program field trials: What works to improve people's actual sorting behaviour?

  • We tested providing apartment buildings / towers with reusable recycling bags to improve in-home sorting systems and reduced bagged recyclables.
  • We also tested providing apartment buildings / towers with behaviourally-informed educational materials (flyers, communal posters, etc.) and set-up of bin bays to promote better waste sorting behaviours.
  • We also tested providing personalised feedback to individual households to improve knowledge and prompt habit change.

Key findings

This program involved BehaviourWorks Australia overseeing the largest known program of coordinated trials in Australia. We found:

  • There are many barriers to good recycling, including physical barriers (i.e. proliferation of complex packaging ), social barriers (i.e. inaccurate advice given from trusted messengers, or judgement from others) and individual barriers (i.e. scepticism, lack of consequences, competing priorities).
  • Targeting contamination (rubbish in the recycling bin) and leakage (recycling in the rubbish bin) at the same time creates confusion. Focusing on what should not be in the recycling bin is more effective at getting it out, and reducing contamination.
  • Traditional education approaches (e.g. signage and flyers) are not sufficient on their own to widely change behaviour. Adding behaviourally-informed messaging to information can help a little but it can also backfire, so should be tested first. Personalised feedback on recycling behaviour is effective in reducing contamination.

Download the Trial Results

For a full summary of our project and its findings, see our Summary Report, or for a quick overview see our Infographic. For a more in-depth read of our individual trials, see our Technical Reports for each trial.

Kerbside recycling summary report
Kerbside recycling infographic

Technical reports:

Facebook experiment Technical Report
Flyer experiment Technical Report
Field trials Technical Report

Resources to run your own trials

Coming soon!

Explore extra resources

We thank our partners for their support and collaborative efforts throughout this program of work, which include the following government departments and organisations highlighted below: