With the best of intentions many organizations give out reusable bags for free. We tested how effective this is to reduce plastic bag use. We got surprising results.
Whether you are an environmental NGO, eco enterprise or governmental agency, you really want to know how you can achieve your goals most effectively. Going through all the valuable behavioral theories and empirical studies, to me it has always been a major goal to bridge the gap in between abstraction and application of my research work.
I found that many activities in the field of environmental organizations aiming to reduce plastic bag use work along two main lines. First, raising environmental awareness, and second, to provide alternatives to plastic bags. We took this approach as a starting point to find the most effective method from four different distribution schemes.
Björn and me explaining our research design to our assistants. They have been of amazing support.
We wanted to know whether there are different effects on people’s use of plastic bags, based on how they received a reusable bag. We chose three different methods.
- Customers received a reusable bag for free
- Customers received a reusable bag for a voluntary price (Also called Pay-What-You-Want scheme, any price -even paying nothing – is ok)
- Customers received a reusable bag for a low cost price of 2000 IDR (this is a subsidized price equal to 15 US-Cents)
- Customers received a reusable bag for free and received a bonus of 5000 IDR (~37 US-Cents) if they shopped at least 5 times within 10 days at the shop using the reusable bag that they received from us.
In each case, the customer also received information about the negative effects of plastic bags to the the environment and people.
If you want to get results that allow you to draw more general conclusions, it is important to do the testing with many people. That’s why we approached more than 1000 customers that resulted in approximately 600 shop customers participating in the project.We looked for them in 20 different shops in 20 randomly selected villages in Gianyar Regency on Bali. In each village and shop we only used one of the methods.
Asking the shop owner to participate in the project
So what where the results? Customers of which group used less plastic bags in the following 4 weeks? You may already have a strong guess about the method that worked best. If you thought of the Bonus method, you were correct! Customers in the “Bonus group” reported to use on average 10 less plastic bags per week. Getting the bonus reward may be a great motivation.
So which method got in second? Actually second place is shared by the customers in the voluntary price and cost price group! Customers in both groups on average used 7 less plastic bags per week. By the way, the voluntary price ended up being higher on average than the cost price. Customers paid more or less 2900 IDR compared to the 2000 IDR for the cost price bag. And now I want to share the most surprising results with you…
The survey 4 weeks after the customers got a reusable bag
By now you know that customers who received a reusable bag for free came in last. What we really did not expect though is that the use of plastic bags has not changed at all! Customers do not use less plastic bags, if the reusable bag was given to them for free. To a certain degree economic theory can help to understand this. Basically you only spend money if you get something in return.
Applied to our case this could mean: You pay for the reusable bag if you are going to use it. Paying for it can hence be seen a bit like a commitment to actually use the reusable bag. Another way trying to understand the result is that if something is given for free, this may indicate it is of low value. Something of low value may be used much less.
Happy with the team at the end of the field experiment
It wouldn’t be right to conclude from these results that giving reusable bags for free never and nowhere has a positive impact on reducing plastic bags. A lot of different factors may lead to differing results in other contexts. For example further educational information to raise environmental awareness may have helped to reduce plastic bag use along providing a free reusable bag.
But if resources are limited, and they are, environmental organizations distributing reusable bags at a price, it can even be a voluntary amount, or a subsidized low price, may be a very effective option. It may not only decrease plastic bag use more effectively, but the lower costs would allow more reusable bags to be distributed and then again reduce plastic bag use even further.
