Three colored waste bins: A trial for behavioral insight

UNDP Bhutan
5 min readApr 22, 2021

Towards understanding households’ values, beliefs, and attitude towards waste, and to help identify favorable attributes that will help nudge households to segregate waste at source.

Green bins for wet waste, blue for dry waste and red for hazardous waste.

Three colored bins for waste segregation were tested in one of the core areas of Thimphu as part of an innovative trial of behavioral interventions on waste management.

Led by the National Environment Commission’s waste flagship program, the trial was carried out from March 13 to April 10. It will provide insights into how and what could encourage households to segregate waste. The Commission plans to roll out the three colored bins to encourage proper waste segregation, critical to better waste recovery and recycling downstream.

Randomized Control Trial

The team with support from The Behavioral Insights Team, Australia, adopted randomized control trial (RTC), considered as gold standard for any experiment. The trial is often used in scientific experiment and rarely so in a social trial because of associated cost. However, since it provides comparable results and measures effectiveness of each intervention, the team designed a trial to answer the following question:

Does providing information or feedback (in addition to household bins) make the biggest difference to improving household segregation of waste?

To test the above hypothesis, the trial was designed to test if providing three colored bins with information had an impact on the household segregation or if feedback had to be included with information for more impact.

Households were divided into those receiving bins with information and those receiving bins with information and feedback. To detect the effectiveness of the intervention, a control group consisting households that do not receive either of them or who would maintain the status quo were also identified.

The 600 plus households were randomly selected from among the 7,000 plus households in Changzamtog and categorized into three groups.

Group 1: Control: 200 households

Group 2: Treatment 1: 200 households were provided with 3 colored bins + information

Group 3: Treatment 2: 200 households were provided with 3 colored bins + information + feedback

The neighborhood was identified for its good representation of households with diverse needs and socio-economic status. Random selection and allocation of the household in separate groups allowed cancellation of our biasness.

The trial report is expected by April end.

Insights from the enumerators

One of the positive impacts of the three coloured bins trial was the change in attitude of enumerators towards waste. The experiment engaged 62 Desuups and six environment inspectors as enumerators. Their commitment towards the trial contributed immensely to the success of the data collection. The experience sparked changes in their attitude towards the waste collectors and service providers.

We thought it was going to be an easy task but the first day of our survey, we realized it was challenging and tedious. Food scrapes and other waste from outside the surrounding were found in dry waste bins. Segregation was not at all meticulous. We came across condoms, torn underwear, metals and broken glasses while sifting through the waste. The survey indirectly made us cultivate new lessons every collection day.”

“We saw some improvement in waste segregation in two households in the second week after they were sent feedback via SMS.”

“I experienced the work of a waste segregator. It is a difficult job.”

The experience

RCT can be as expensive as you want it to be: In a typical RCT, there may be only two arms (yes, the RCT gurus call the groups as arms), but depending on the objective of your trial there can be multiple arms. Obviously, greater the number and size of arms, greater the costs! It’s always better to have few when you are starting. Cost implications as well as capacity and feasibility in terms of managing fieldwork were some determining factors for the choices we made.

Think about scalability and sustainability: One thing that we need to be conscious about is the scalability aspect. During the prototype phase, one should attempt to minimize any resource intensive elements of the experiment. For instance, one of the treatment arms required providing feedback to the households on the quality of waste segregation. While some proposed one-on-one feedback, wherein each household would get customized feedback, including such laborious component would mean hiring more enumerators, lengthening processes and, therefore, making scalability difficult. So, instead we adopted individual SMS feedback which is closer to the SMS blast.

Designing the experiment with direct actors involved in mind: The ultimate users of the three colored bins are households, and not commercial units or institutions. So, it is vital that we prototype with the clients in mind to remove any confusing factors that might impact the outcome of the experiment, whether it is shape and size of the bins or the schedule of data collection.

Opportunity to address challenges (logistical): Often things that looks right on paper does not work in the field. Prototyping provides us with an avenue to continuously develop the experiment further. Being open to advice and suggestions from everyone about everything, such as collaboration and different perspectives, help refine the processes.

The question on downstream waste treatment still lingers. Households and enumerators were curious where the waste collected were disposed. The Waste Flagship Program has plans laid out to build compost plant, material recovery center and drop-off centers among others to promote circular economy.

Contributed by Kunzang Wangmo, Head of Experimentation and Sonam Choki, Innovation Solution Mapper and Explorer, Accelerator Lab Team, UNDP Bhutan

We would like to extend our gratitude to the NECS, Thimphu Thromde and DeSuung Office in partnering with the Accelerator Lab in the learning cycle and we look forward to co-creating ideas and solutions for effective waste management in Bhutan.

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UNDP Bhutan

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