Plans to promote participant retention
The teachers in the study are followed up closely throughout the process, and they receive emails three to four times each month with reminders and motivating comments and always before and after testing. The first author has close contact with the teachers and delivers memory cards for the video cameras to all schools before testing and collects the memory cards immediately after the testing is finished. The first author is also available via email and phone throughout the intervention period and visits the schools when necessary and at request of the teachers. The teachers also send monthly summaries by email (anonymously) so that the first author has an overview of what and how much is being done at any given time. This helps us to intervene early if someone is lagging behind in the study or do not adhere to the protocol. If participants drop out of the study for legitimate reasons such as illness, moving, behavioral changes, or that parents want to withdraw them from the study, there is no plan for further follow-up. Data will be registered as missing data.Regarding the participants retention (students), we have the following strategies: it is a goal that the students do the work sessions once per day. The teachers have been instructed in how to motivate the students, by using reinforce that students prefer. It is also important to involve the parents as a strategy for adherence, e.g., sending updates to the parents so they also can motivate their children to participate in the intervention.