Schools that registered for participation were randomized to the aforementioned four experimental conditions. We assessed the level of financial literacy of all students before as well as after followed the course. Students assigned to the control group completed the same tests at the same time as students in the treatment groups, without following the course between the tests. The experiment was implemented in two waves: In the first wave, students in grade 8 (the second year of secondary education in Flanders, age 13-14) participated in the experiment. In the second wave, students in grade 9 (the third year of secondary education in Flanders age 14-15) participated, completing the same course and questionnaires.
Before the intervention, all students (control group + treatment groups) filled in an online questionnaire to test their financial literacy. Students also reported several personal characteristics like gender, school grades, and socio-economic background. Teachers in the treatment groups received the course material, including instructions for implementation, after all students filled in the questionnaire.
Approximately one month after filling in the first test, students in the treatment groups followed a 4-hour financial education course on means of payment. The course material was designed as a serious game and students had to solve questions on means of payment in groups of two students. Students could find the necessary information to solve the questions in a paper booklet that complemented the digital game. As incentive for good performance during the course, the winning team received a small present. All course material was developed by high school teachers with consideration for the age and the ability of the students.
In treatment groups 2 and 3 (see above), students had to complete a homework assignment before the start of the course. In treatment group 2, students did the homework without their parents. In treatment group 3, students did a variation of the homework assignment together with their parents.
At the end of the course, students filled in a test to measure financial knowledge and financial behavior. At the same time, students in the control group also filled in this test without having followed the course. This test was designed as variation of the first test, i.e. with questions analogous to the test students completed before the intervention.