Table 2.

Study measures and definitions.

Variable name	Definition
Amount spent on advertising per trial (Aus $)	Facebook and Instagram advertising costs per trial in Australian dollars.
Impressions	Number of times study advertisements were viewed.
Reach	Number of people that viewed study advertisements.
Link clicks	Number of times that links to study advertisements were clicked on.
Unique link clicks	Number of people that clicked on study advertisement links, regardless of how many times they clicked on a link.
Click through rate	The percentage of people who viewed and then clicked on the study advertisement. This was calculated by dividing the total number of clicks by the total number of impressions multiplied by 100. Click-through rates measure how successful the study advertisements are in capturing people’s attention.
Number of students screened	Number of people who completed screening.
Number of eligible students	Number of people who were eligible to take part in the study.
Number of students who downloaded the study app	Number of people who downloaded the study app from Google Play or the App Store.
Number of students who completed a trial	Number of people who completed the 3 phases of the study (baseline, midpoint, and post).
Costs per screened	Costs per person who completed the screening questionnaires in Australian dollars.
Costs per eligible	Costs per person who was eligible to participate in the study in Australian dollars.
Costs per downloaded	Costs per person who downloaded the study app from Google Play or the App Store in Australian dollars.
Costs per completed	Costs per person who completed all three phases of the study in Australian dollars.