Ecological Momentary Assessments (EMA) for the Exposure to Alcohol Advertisements and Promotion of Alcohol Drinking Culture (PADC) in University Students

1. Study design The proposed project is a combination of (1) a time-based system-triggered EMA, which will collect real-time exposure to alcohol advertisements and PADC, and (2) longitudinal surveys involving university students who are current alcohol users. Consented participants will be individually randomized to 2 groups - the EMA and non-EMA group. The EMA group will first complete a baseline questionnaire, followed by 5 regularly prompted EMA surveys via a smartphone application (App) every day for 14 consecutive days. The EMA includes questions of the self-reported exposure to and /or responses to alcohol advertising PADC. 2 weeks after the completion of the EMA, they will be contacted to complete a telephone follow-up survey. The non-EMA group will only complete the baseline and the follow-up surveys.
2. Subjects The study targets to recruit 100 students (EMA: 50; non-EMA: 50) who are Hong Kong residents and are studying in undergraduate or postgraduate programmes in any Hong Kong tertiary institutions. Other inclusion criteria will include (1) aged between 18 and 35 years, (2) using a mobile smartphone with internet access, (3) drank any alcohol in past 30 days (current drinkers), (4) he/she will stay in Hong Kong during the 2-week EMA study period, and (5) able to read and write in Chinese.
3. Procedures A mass email containing the study information will be sent to all undergraduate and postgraduate HKU students for recruitment. Also, subject recruitment ad will be posted in different online discussion boards. Voluntary participants can directly contact our recruitment staff via telephone, email or submission of online application form. The staff will assess the participants' eligibility by telephone. The staff will then randomise the eligible participants into either the EMA or non-EMA group and deliver consent forms to the participants face-to-face before conducting the baseline survey. Sequentially numbered, opaque sealed envelope (SNOSE) will be used for the random allocation. All participants will be invited to join a briefing session where the staff will administer the baseline survey. The staff will help the participants in the EMA group to install and set up the EMA App. The briefing will also emphasise the role of EMA participants that they should perform their normal activities as usual instead of finding out the alcohol advertisements and PADC intentionally. Within 2 weeks after completing the baseline survey, participants in EMA group will complete 5 EMAs prompted regularly every day for 14 consecutive days. The participants will then be contacted for a follow-up survey 2 weeks after the completion of EMA. Participants in non-EMA group will only complete a baseline questionnaire and a follow-up survey.
4. Incentives for participants The EMA validity largely relies on the participants' compliance, therefore an attractive incentive is needed. All participants will be given a HK$100 gift voucher upon the completion of the baseline survey and 2-week follow-up survey. In addition, participants in EMA group will accumulate HK$15 gift voucher for completing 3 EMA surveys within each day in their account. If they complete all EMA surveys within a day, they can further accumulate HK$10 gift voucher. EMA participants who have successfully completed all EMAs in the 14-day period will be given additional $50 gift voucher.
5. EMA app An EMA App will be developed to administer the regular prompts automatically. To protect the privacy of the participants, no personal information (e.g. names and telephone numbers) will be collected by the App. Only a 5-digit case number will be used for identification. Unless otherwise specified, the case number will be the last 5 digits of subject's phone number. Once the App is successfully installed, the user will be asked to choose a start date for the 14 consecutive days study period within the coming 2 weeks and set up awake time from 9:00am to 12:00nn in these study days to undertake the regularly-prompting EMA.

On each study day, the App will regularly prompt the participants to complete a questionnaire about their recent exposure to alcohol advertisements and PADC every 3 hours for 5 times. For example, if a participant sets the awake time to 9:00am, he will be asked to complete an EMA survey at 9:00am, 12:00nn, 3:00pm, 6:00pm and 9:00pm for the study period.

Each EMA survey will take about 1 minute to complete. If the user cannot respond to the EMA survey prompt immediately, he/she could choose to postpone the prompt for 5 minutes / 30 minutes. The EMA prompt will be re-generated to remind the user again. Each prompts not responded for 3 mins, or postponed more than once will be regarded as non-response.

All the above data, including the date and time of completing the EMA survey and responses to the prompts will be sent to our server immediately. Participants can check their progress and record about their EMA surveys completion status and the amount of rewarded gift voucher in the EMA App. 6. Questionnaire design

1. Baseline questionnaire There are 4 parts in the baseline questionnaire to investigate the participants' drinking history, their awareness of alcohol advertising and PADC, and their attitude towards alcohol drinking culture, alcohol advertisements and alcohol advertising and marketing policy.