Procedures
Smoking causes mouth cancer, smoking behaviors
EMA
At their first lab visit, participants completed some baseline surveys about demographic information and smoking behaviors, and provided a sample of exhaled air to verify smoking status (recording greater than 7 ppm carbon monoxide breath sample as measured by piCO Simple SmokerlyzerEach day, participants were required to complete an evening report, rating their quitting intentions, risk perceptions, and self-efficacy beliefs. The items used to assess quitting intentions and self-efficacy beliefs were derived from surveys published in previous studies and measured participants’ agreement with a series of statements on scales of 1–10 and 1–9 respectively. Risk perceptions were measured on a scale of 1–7. Details of these questions can be found in the supplementary materials. During these end-of-day reports, participants were also asked to specify which of the Australian HWLs was currently on their tobacco packaging and were required to take a photograph of this HWL using the device.After a week of baseline monitoring, participants returned to the lab for a second study visit. At this visit, data were downloaded from devices and additional training on the monitoring procedures was provided to participants with poor compliance (at or below 80% completion of surveys issued) by study staff. Next, participants were randomized (un-blinded) to either the control or experimental groups and received adhesive labels for the front and back of their cigarette packs. Participants in the experimental group received adhesive HWLs that were modified from the current HWLs in Australia: Here, we used seven of the images in circulation in Australia (see Examples of labels given to participants in the experimental group. Labels for the front of pack (top row) featured short slogans and subtitles which were expanded in line with the theme of the image on the back of pack (bottom row). “Don’t let others breathe your smoke” otherwise known as “the boy with the oxygen mask” used with permission from the European Union; “Smoking causes mouth cancer” used with permission from Dr Christopher Hughes on behalf of St Vincent’s Hospital, Sydney.At the end of 14-day experimental phase participants completed their third lab visit, returned their EMA devices and were debriefed. Participants were reimbursed for their time with vouchers which were issued at each study visit (AUD$90 in total). Compliance with EMA protocol was incentivized by offering an additional $20 voucher for participants who answered at least 80% of the random prompt surveys issued.