Moral actions, recycling and pro-social behavior

We will conduct an intervention to test whether performing a good action immediately after receiving an environmental information campaign influences the campaign’s effectiveness on recycling behavior. Specifically, we will offer a randomly selected sub-sample of participants the opportunity to make a contingent donation in the event of winning a monetary prize. Our analysis will assess whether being offered the chance to donate affects the campaign’s impact on waste separation.

2025-04-01

2026-04-30

The key variable will be a dummy variable that indicates for each week whether the household used the bio-waste sorting bin (1) or not (0). Thanks to an agreement with the local waste management company, we will have access to this information both before and after the treatment.

The main constructed variable will be the average of the primary dummy variable over time for each household, which indicates the proportion of weeks that each household makes use of bio-waste sorting bins. We will also aggregate the primary dummy variable across households in a given week, to obtain the proportion of households that make use of bio-waste sorting bins on that week.

Besides real behavior (recycling), we will also measure the effect of the treatment on (i) perception on the importance of recycling; (ii) intentions to recycle; and (iii) moral self-concept.

(i) Perception on the importance of recycling will be measured with the self-reported answer to the item: "How important do you consider recycling bio-waste for fighting climate change?" (5 possible answers from "Not important at all" to "Very important").

(ii) Intentions to recycle will be measured by answers to the item: "How likely do you think it is that from now on your household will recycle bio-waste? (5 possible answers: "Definitely not", "Probably not", ""Maybe yes maybe no, "Probably yes", "Definitely yes").
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(iii) Self-concept will be evaluated according to the question. "I am helpful with other people"(7 possible answers from ``Totally disagree" to ``Totally agree").

We will conduct an intervention to test whether performing a good action immediately after participating in an environmental information campaign influences the campaign’s effectiveness on recycling behavior. Specifically, we will offer a randomly selected sub-sample of participants the opportunity to make a contingent donation in the event of winning a monetary prize. Our analysis will assess whether being offered the chance to donate affects the campaign’s impact on waste separation.

Not available

Randomization will be performed by computer using the available option of the Qualtrics platform (or similar).
For balancing tests, pre-intervention values of the primary outcome will be used.

Participating households.

No

Between 500 and 2000 participants (one from each household), depending on recruitment capacity.

Number of recruitment participants times the number of weeks analyzed

50% to control group and 50% to treatment group

According to data from other studies in the same setting, the average household in the city of Palma uses bio-waste sorting bins with a weekly frequency of 0.1876207, showing a standard deviation of 0.324002. For a power analysis of 80%, a sample size of at least 500 households per treatment arm guarantees a minimum detectable effect of |0.0610| in the use frequency at 95% confidence and |0.0745| at 99% confidence.