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Trial registered on ANZCTR

Registration number
Ethics application status
Date submitted
Date registered
Date last updated
Type of registration
Prospectively registered

Titles & IDs
Public title
Making the most of plain packaging: using self-efficacy messages printed on cigarette packaging to help smokers to quit.
Scientific title
Making the most of plain packaging: using self-efficacy messages on cigarette packaging to promote smoking cessation.
Secondary ID [1] 289557 0
Universal Trial Number (UTN)
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
tobacco use 299280 0
Condition category
Condition code
Public Health 299277 299277 0 0
Other public health
Mental Health 299295 299295 0 0

Study type
Description of intervention(s) / exposure
This study will recruit a community sample of smokers for a three week trial assessing the effect of adding self-efficacy messages to the graphic warning images displayed on tobacco packaging. The trial consists of a baseline phase of one week, during which all participants smoke from packaging displaying the current government mandated health warning labels (HWLs), and a two week experimental phase wherein participants will be randomly assigned to a control or an experimental group and will be exposed to different HWLs accordingly. All participants will be required to stick an adhesive label over the warning label on the packaging of their tobacco (which they have purchased as usual) at the time of first opening. Those in the control group will have labels identical to the standard HWLs currently in circulation. Those in the experimental group will have labels with the same graphic images, but will have a study-specific self-efficacy message in place of the usual text warning. All participants will be required to carry a hand-held computer with them at all times for the duration of the study and will complete frequent assessments recording their smoking- related cognitions and behaviours as well as take photographs of their tobacco packaging with study-specific HWLs in place in order to monitor compliance. . Participants will also visit a laboratory at the University of Tasmania three times during the course of the trial and provide samples of exhaled air to verify their self-reported smoking behaviour by measuring carbon monoxide levels. These visits would be scheduled at the beginning of the baseline phase, at the conclusion of the baseline phase and at the end of the experimental phase. Efficacy message labels will target response efficacy, self-efficacy and control perceptions and will feature an alternative warning statement (the large, bold text above the graphic image) and and alternative explanatory message (the smaller, more detailed text below the image on the back of the package). Efficacy messages will vary according to the nature of the graphic image with which they are combined. For example, a warning statement combined with and image of a damaged heart might say "DON’T SMOKE THIS ONE AND UNCLOG YOUR ARTERIES.Use nicotine patches and gums in combination to beat cravings" and feature an explanatory message such as: "If you quit smoking now, your risk of coronary heart disease will drop by half in a years’ time. It’s not too late. You can talk to your GP to get nicotine patches to overcome your cravings. Quitting at any age is well worth the effort".
Intervention code [1] 295149 0
Intervention code [2] 295169 0
Treatment: Other
Intervention code [3] 295172 0
Comparator / control treatment
Half of the participants will be assigned to a control group. During the baseline phase, the control group will smoke their tobacco as usual from original packaging with standard government mandated health warning labels. During the experimental phase of the study, the control group will be issued with sets of adhesive health warning labels identical to those required by law to be printed on tobacco packaging and will be required to stick these over the original health warning labels. This will control for the possibility of extraneous effects in the experimental group associated with the attentional processes involved in sticking warning labels to the tobacco packaging.
Control group

Primary outcome [1] 298761 0
level of intention to quit smoking as assessed using two questions with numerical rating scales on the hand-held computer device and also via questionnaires with numerical rating scales at lab visits. The questions comprising these scales have been used in previous studies which have investigated intention to quit (e.g. Orbell, et al. (2009). Social–cognitive beliefs, alcohol, and tobacco use: A prospective community study of change following a ban on smoking in public places. Health Psychology, 28(6), 753.; Schuez, et al.. (2016). Immediate effects of plain packaging health warnings on quitting intention and potential mediators: Results from two ecological momentary assessment studies. Psychology of Addictive Behaviors, 30(2), 220.)
Timepoint [1] 298761 0
1. Daily:both after exposure to warning labels (each time a participant logs a cigarette); in response to random prompts from the device (which occur 4-5 times each day); when completing a scheduled evening report.
2. At lab visits: at the end of the baseline (day 7) and experimental (day 21) phases.
Primary outcome [2] 298762 0
Proportion of participants with a reduction in the number of cigarettes smoked daily as assessed by the number of cigarettes logged on the hand-held computer and on questionnaires at lab visits. The reported number of cigarettes participants smoke daily will be verified by measuring the carbon monoxide levels in exhaled air. This method of measuring smoking behaviour has been validated previously and shown to be associated with high levels of participant compliance ( Schuez, et al.. (2014). Compliance with an EMA monitoring protocol and its relationship with participant and smoking characteristics. nicotine & tobacco research, 16(Suppl 2), S88-S92.)
Timepoint [2] 298762 0
1. Daily: recorded on hand held devices.
2. Lab visits: at the end of the baseline phase (day 7) and at the end of the experimental phase (day 21).
Primary outcome [3] 298763 0
level of risk perception as assessed with numerical rating scales on hand held devices and on questionnaires at lab visits. The questions comprising these scales have been used previously to assess risk perception (e.g. Orbell, et al. (2009). Social–cognitive beliefs, alcohol, and tobacco use: A prospective community study of change following a ban on smoking in public places. Health Psychology, 28(6), 753; Schuez, N., & Ferguson, S. G. (2015). Australian smokers’ and nonsmokers’exposure to anti-smoking warnings in day-to-day life: A pilot study. Nicotine & Tobacco Research, 17, 876 – 881)
Timepoint [3] 298763 0
1. daily: after exposure to warning labels (each time participants log a cigarette).
2. lab visits: at the end of the baseline phase (day 7) and the end of the experimental phase (day 21).
Secondary outcome [1] 325194 0
Timepoint [1] 325194 0

Key inclusion criteria
Current smokers from the greater Hobart area, who have smoked a minimum of ten cigarettes daily for the past three years. They must have an adequate grasp of the English language and not be interested in quitting in the next month
Minimum age
18 Years
Maximum age
No limit
Both males and females
Can healthy volunteers participate?
Key exclusion criteria
Pregnancy, cognitive impairment, intellectual disability, mental illness.

Study design
Purpose of the study
Allocation to intervention
Randomised controlled trial
Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)
central randomisation
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
computerised sequence generation
Masking / blinding
Open (masking not used)
Who is / are masked / blinded?

Intervention assignment
Other design features
Not Applicable
Type of endpoint(s)
Statistical methods / analysis
The proposed sample size (n=60; 30 participants per group) was determined by the requirements of the primary research questions – namely, detecting differences in intention quitting behaviours and risk perception scores between the modified warning label and the control group at the end of the treatment period. Estimates of the expected effect sizes are based on two systematic reviews examining the combination of fear appeals and self-efficacy. Pooling these effect sizes in a random-effects meta-analytic model yields a combined effect size of d = .76. In order to detect an effect of this size with a power of .8 and an alpha of .05, 58 participants are needed. Moreover, Montecarlo simulation studies suggest that 60 participants with the intended number of assessments are sufficient for random effects analyses (assessments [level-1] nested in participants [level-2]) yielding unbiased standard errors and variance components.

Multilevel (linear mixed effect) models will be used to analyse the experimental data and the moderated mediational pathways of the intervention. These analyses allow for an unequal number of observations across individuals. Thus, we will be able to use all available data and do not need to exclude data based on level of completeness. We will run latent growth curve models to test for within-person changes in intention and the suggested mediators across the baseline and experimental phases. We will test for differences in slopes between the experimental groups (according to the hypotheses, the slopes for intention and its predictors should not be different from zero in the control group, whereas the slopes will be higher in the experimental group).
We will compare participants’ quit intentions and their mediators after encountering a warning to intentions and mediators at random times of the day. For this, we will run a multilevel moderated mediation model with intention to quit as dependent variable, type of assessment (immediately post-cigarette vs. random prompt) as the independent variable, and defensive reactions as moderator, risk appraisal and self-efficacy as mediators. The experimental group will be treated as moderator to model differential intervention effects. Overall self-efficacy ratings and nicotine dependence/number of cigarettes per day will be tested as moderators of the effects of the intervention on threat management resources and intentions and the effects of intentions on smoking.

Recruitment status
Date of first participant enrolment
Date of last participant enrolment
Date of last data collection
Sample size
Accrual to date
Recruitment in Australia
Recruitment state(s)

Funding & Sponsors
Funding source category [1] 293928 0
Name [1] 293928 0
University of Tasmania
Address [1] 293928 0
Office of Research Services, University of Tasmania, Private Bag 1, Hobart, TAS, 7001
Country [1] 293928 0
Primary sponsor type
Dr. Natalie Schuez
University of Tasmania
School of Health Sciences
Private Bag 135
Hobart, TAS. 7000
Secondary sponsor category [1] 292756 0
Name [1] 292756 0
Dr. Benjamin Schuez
Address [1] 292756 0
University of Tasmania
Psychology, School of Medicine, Faculty of Health.
Private Bag 30.
Hobart, TAS, 7001
Country [1] 292756 0
Secondary sponsor category [2] 292757 0
Name [2] 292757 0
Dr. Stuart Ferguson
Address [2] 292757 0
University of Tasmania
Pharmacy, School of Medicine, Faculty of Health
Private Bag 34, Hobart TAS 7001
Country [2] 292757 0
Secondary sponsor category [3] 292758 0
Name [3] 292758 0
Lillian Brinken
Address [3] 292758 0
University of Tasmania
Psychology, School of Medicine, Faculty of Health.
Private Bag 30.
Hobart, TAS, 7001
Country [3] 292758 0

Ethics approval
Ethics application status
Ethics committee name [1] 295350 0
Tasmanian Health and Medical Human Research Ethics Committee
Ethics committee address [1] 295350 0
Office of Research Services
University of Tasmania
Private Bag 01
Hobart TAS 7001
Ethics committee country [1] 295350 0
Date submitted for ethics approval [1] 295350 0
Approval date [1] 295350 0
Ethics approval number [1] 295350 0

Brief summary
The proposed study would investigate the effectiveness of the graphic warning labels currently featured on tobacco products and whether they can be enhanced by adding messages which target self-efficacy. Self-efficacy can be understood as the level of confidence to which a person believes in their own capacity to carry out a given action, despite potentially arising difficulties. Manipulating self-efficacy beliefs and has been observed to enhance the effectiveness of confronting or threatening health messages (‘fear-appeals’), which are often found to backfire. The current tobacco warning labels used in Australia make extensive use of fear-appeals.

This study would measure whether sticking self-efficacy messages onto current warning labels (while ensuring the graphic images remain visible) can influence intentions and behaviours observed to be related to quitting smoking among a group of sixty tobacco smokers. A study-provided smartphone would be used to assess perceptions of personal health risks due to smoking, intentions and behaviours several times a day over a three week period.

The first week of the study would be a baseline phase in which all participants report their risk perceptions, intentions and behaviours while continuing to smoke from the standard tobacco packaging. The second and third week would be the experimental phase, during which participants would be randomly divided into two groups. The experimental group would smoke from packages with self-efficacy messages attached and the control group would smoke from packages with current warning labels. All participants would continue to report their risk perceptions, intentions and behaviours, allowing researchers to assess changes between the two groups as well as changes within individual participants by comparing the baseline phase to the experimental phase.

Participants would visit the laboratory three times during the course of the study: an induction visit at the beginning; a visit at the end of the baseline phase during which randomisation will take place, and a visit at the end of the experimental phase. At each visit they would be required to give a sample of exhaled breath for the measurement of carbon monoxide content. Carbon monoxide levels provide an indication of how much a person smokes and allows researchers to check how reliably participants report their smoking behaviour. Moreover, they will complete a brief assessment of their overall risk perceptions, intention and smoking behaviour during the last week. This will allow us to compare stable measures of the proposed determinants of behaviour with real-time measures.

During the final visit, participants will be debriefed and asked to provide feedback. Moreover, at this time, participants in the control group will receive the same set of study-specific labels the experimental group received during the experimental phase, thus they will have access to the same intervention material after the study is completed.
Trial website
Trial related presentations / publications
Public notes

Principal investigator
Name 66962 0
Dr Natalie Schuez
Address 66962 0
University of Tasmania
School of Health Sciences
Private Bag 135
Hobart TAS 7000
Country 66962 0
Phone 66962 0
+61 3 62264606
Fax 66962 0
Email 66962 0
Contact person for public queries
Name 66963 0
Dr Benjamin Schuez
Address 66963 0
University of Tasmania.
Psychology, School of Medicine, Faculty of Health
Private Bag 30,
Hobart TAS 7001
Country 66963 0
Phone 66963 0
+61 3 6226 7471
Fax 66963 0
Email 66963 0
Contact person for scientific queries
Name 66964 0
Dr Benjamin Schuez
Address 66964 0
University of Tasmania.
Psychology, School of Medicine, Faculty of Health
Private Bag 30,
Hobart TAS 7001
Country 66964 0
Phone 66964 0
+61 3 6226 7471
Fax 66964 0
Email 66964 0

No information has been provided regarding IPD availability
Summary results
Have study results been published in a peer-reviewed journal?
Other publications
Have study results been made publicly available in another format?
Results – basic reporting
Results – plain English summary