The intervention covers no fewer than four classroom sessions, though participating teachers have discretion to add additional material. In the first session, all students are given an exercise: to measure, each day over a period of ten days, the amount of waste generated in their household or the household they are visiting that day. Between one and three weeks after the conclusion of these exercises, the second session occurs. Students then listen to a brief lecture on waste and the environment, participate in a subsequent group discussion, and finally play an educational game where they answer quiz questions on waste and tasked with correctly sorting cards representing different waste fractions. Finally, the third and fourth sessions consist of an extended reading exercise (with associated quiz questions) on the UN Sustainable Development Goals. Students may complete this exercise alone or in small groups.
As part of the initial home assignment, each student fills in a form provided by the experimenters. This is the main data source from the intervention itself. One of the fields specifies the address where, for each day, the assignment was carried out. These addresses are then combined with household-level waste data, allowing estimation of ATEs on waste amounts among households where a student was treated. The presence of (many) non-participant households in the waste data allows us to to construct a suitable non-randomized control group through matching and/or weighting (synthetic control) on pre-intervention waste amounts. The pool of potential control units for a given participant household consists of non-participant households in the same area.