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Trial registered on ANZCTR


Registration number
ACTRN12618001212246
Ethics application status
Approved
Date submitted
14/07/2018
Date registered
19/07/2018
Date last updated
4/03/2019
Date data sharing statement initially provided
19/11/2018
Date results information initially provided
4/03/2019
Type of registration
Prospectively registered

Titles & IDs
Public title
Changing driver behaviour during floods using an e-health imagery intervention
Scientific title
Testing a novel implementation imagery e-health intervention to change driver behaviour during floods: A randomised controlled trial
Secondary ID [1] 295557 0
None
Universal Trial Number (UTN)
U1111-1217-4684
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Promoting safe driving behaviour during floods to prevent drowning and injury 308828 0
Condition category
Condition code
Injuries and Accidents 307756 307756 0 0
Other injuries and accidents

Intervention/exposure
Study type
Interventional
Description of intervention(s) / exposure
The intervention is an online tool that uses a series of infographic videos in which participants are prompted to engage in exercises using imagery and planning to change behaviour their beliefs and intentions toward driving into floodwater. The intervention integrates implementation intentions and mental imagery behaviour change techniques to form a novel implementation imagery intervention.

The study will be administered online using the Qualtrics online survey tool. All participants will complete a baseline survey, an activity (different for intervention and control groups), and a survey immediately post-intervention at the first time point. Four weeks later, all participants will complete a follow-up survey.

Between the baseline and post-intervention surveys, participants randomly assigned to the intervention group will complete a series of activities constituting the implementation imagery intervention. The activities will run for 10 to 15 minutes and will be delivered in the form of videos embedded within the online survey tool. Video 1 will include factual information to educate participants about the risks of driving into floodwater and will then provide information to encourage participants to form a goal of avoiding driving into floodwater if they encounter it on their route. Video 2 will guide participants through a process mental simulation followed by a short writing task where participants will be asked to record the things they imagined. Video 3 will guide participants through an outcome mental simulation followed by a short writing task where participants will be asked to record the things they imagined.

Two questions will be embedded within the baseline (T1) survey to assess whether participants are reading instructions properly or carelessly responding (Maniaci & Rogge, 2014; Schroder, Dawood, Yalch, Donnellan, & Moser, 2016). The questions instruct the choice of a particular answer so that it is not possible to answer the question incorrectly if the item is read carefully (e.g., “please choose option two to ensure you are paying attention”). Participants who do not answer both of the items correctly will be excluded prior to randomisation.
Fidelity of the intervention will also be assessed using a modified version of a four-item scale developed by Knäuper et al. (2011). The items assess vividness, clarity, detail, and ease of imagery on 7-point scales (e.g., “How CLEAR was the mental image that you had of yourself avoiding driving through the floodwater?”).
Intervention code [1] 301856 0
Behaviour
Comparator / control treatment
Between the baseline and post-intervention surveys, participants randomly assigned to the control group will watch a short video. This video will present the factual information to educate participants about the risks of driving into floodwater that is provided in the first part of Video 1 administered to the intervention group.
Control group
Active

Outcomes
Primary outcome [1] 306743 0
Change in intention toward driving through floodwater.

Note: All outcome measures are contained within a study-specific questionnaire delivered through the Qualtrics online tool. All outcome measures are based on theoretical guidelines for measurement of these constructs. Please see attached file for items used to measure each construct.
Timepoint [1] 306743 0
Baseline (T1), immediately post-intervention (T2) [primary timepoint], 1-month follow-up post-intervention (T3).
Secondary outcome [1] 349418 0
Change in attitudes toward driving through floodwater.

Note: All outcome measures are contained within a study-specific questionnaire delivered through the Qualtrics online tool. All outcome measures are based on theoretical guidelines for measurement of these constructs. Please see attached file for items used to measure each construct.
Timepoint [1] 349418 0
Baseline (T1), immediately post-intervention (T2), 1-month follow-up post-intervention (T3).
Secondary outcome [2] 349419 0
Change in subjective norm regarding driving through floodwater.

Note: All outcome measures are contained within a study-specific questionnaire delivered through the Qualtrics online tool. All outcome measures are based on theoretical guidelines for measurement of these constructs. Please see attached file for items used to measure each construct.
Timepoint [2] 349419 0
Baseline (T1), immediately post-intervention (T2), 1-month follow-up post-intervention (T3).
Secondary outcome [3] 349639 0
Change in perceived behavioural control regarding driving through floodwater.

Note: All outcome measures are contained within a study-specific questionnaire delivered through the Qualtrics online tool. All outcome measures are based on theoretical guidelines for measurement of these constructs. Please see attached file for items used to measure each construct.
Timepoint [3] 349639 0
Baseline (T1), immediately post-intervention (T2), 1-month follow-up post-intervention (T3).
Secondary outcome [4] 349640 0
Change in risk perception regarding driving through floodwater.

Note: All outcome measures are contained within a study-specific questionnaire delivered through the Qualtrics online tool. All outcome measures are based on theoretical guidelines for measurement of these constructs. Please see attached file for items used to measure each construct.
Timepoint [4] 349640 0
Baseline (T1), immediately post-intervention (T2), 1-month follow-up post-intervention (T3).
Secondary outcome [5] 349641 0
Change in perceived susceptibility to the consequences driving through floodwater.

Note: All outcome measures are contained within a study-specific questionnaire delivered through the Qualtrics online tool. All outcome measures are based on theoretical guidelines for measurement of these constructs. Please see attached file for items used to measure each construct.
Timepoint [5] 349641 0
Baseline (T1), immediately post-intervention (T2), 1-month follow-up post-intervention (T3).
Secondary outcome [6] 349642 0
Change in perceived severity of the consequences of driving through floodwater.

Note: All outcome measures are contained within a study-specific questionnaire delivered through the Qualtrics online tool. All outcome measures are based on theoretical guidelines for measurement of these constructs. Please see attached file for items used to measure each construct.
Timepoint [6] 349642 0
Baseline (T1), immediately post-intervention (T2), 1-month follow-up post-intervention (T3).
Secondary outcome [7] 349643 0
Change in anticipated regret regarding driving through floodwater.

Note: All outcome measures are contained within a study-specific questionnaire delivered through the Qualtrics online tool. All outcome measures are based on theoretical guidelines for measurement of these constructs. Please see attached file for items used to measure each construct.
Timepoint [7] 349643 0
Baseline (T1), immediately post-intervention (T2), 1-month follow-up post-intervention (T3).
Secondary outcome [8] 349644 0
Change in barrier self-efficacy regarding avoiding driving through floodwater.

Note: All outcome measures are contained within a study-specific questionnaire delivered through the Qualtrics online tool. All outcome measures are based on theoretical guidelines for measurement of these constructs. Please see attached file for items used to measure each construct.
Timepoint [8] 349644 0
Baseline (T1), immediately post-intervention (T2), 1-month follow-up post-intervention (T3).
Secondary outcome [9] 349645 0
Change in action planning regarding avoiding driving through floodwater.

Note: All outcome measures are contained within a study-specific questionnaire delivered through the Qualtrics online tool. All outcome measures are based on theoretical guidelines for measurement of these constructs. Please see attached file for items used to measure each construct.
Timepoint [9] 349645 0
Baseline (T1), immediately post-intervention (T2), 1-month follow-up post-intervention (T3).

Eligibility
Key inclusion criteria
- Australian resident
- Holder of a registered driver’s licence (excluding learner’s permit)
- Only one household member may participate in the survey
Minimum age
17 Years
Maximum age
No limit
Gender
Both males and females
Can healthy volunteers participate?
Yes
Key exclusion criteria
Nil

Study design
Purpose of the study
Prevention
Allocation to intervention
Randomised controlled trial
Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)
Allocation concealed. Eligibility screened online by survey tool. Allocation to groups conducted by Qualtrics software (central randomisation) following consent procedure and baseline survey.
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
Simple randomisation using Qualtrics embedded randomiser.
Masking / blinding
Blinded (masking used)
Who is / are masked / blinded?
The people receiving the treatment/s
The people administering the treatment/s
The people assessing the outcomes
Intervention assignment
Parallel
Other design features
All aspects of the study will be administered online using Qualtrics online survey tool.. Participants will be screened on the following demographic characteristics and quotas will be imposed to ensure that the sample is proportional to the distribution of flood-related transport deaths in the Australian population:
- Age
- Sex
- Region (state and metropolitan vs. rural)
- Household income
Phase
Not Applicable
Type of endpoint(s)
Efficacy
Statistical methods / analysis
Hypotheses will be tested using a series of mixed-model ANCOVAs. In the analyses, condition/group will be a between-subjects variable; Time (T1, T2, T3) will be a within-subjects variable; and the primary outcome (intention) and secondary outcomes (attitude, subjective norm, perceived behavioural control, risk perception, anticipated regret, perceived susceptibility, barrier self-efficacy, action planning) will be separate dependent variables. Consistent with the approach taken in our prior work (Hamilton, et al., 2018), demographic variables (gender, age, relationship status, educational level, number of years driving, number of children, and past frequency of driving through floodwaters) will be included as covariates in the analyses. Mental imagery ability and willingness to form a goal to avoid driving into floodwater will also be included as covariates.
An a priori power analysis was conducted using G*Power v3.1 for an ANCOVA model estimating fixed effects, main effects, and interactions. The effect size was set to f = .25 (corresponding to the effect size of intention from pre- to post-intervention in Hamilton, Peden, Keech & Hagger, 2018), with power set to .95 and a=.01 (adjusted to protect from inflation of type I error rate due to multiple tests). Nine covariates were also specified. The total minimum sample size required is n = 289. Target sample size will therefore be 460 (230 per group) at baseline to allow for up to 35% attrition at follow-up (n=300; n=150 per group).

Recruitment
Recruitment status
Completed
Date of first participant enrolment
Anticipated
Actual
Date of last participant enrolment
Anticipated
Actual
Date of last data collection
Anticipated
Actual
Sample size
Target
Accrual to date
Final
Recruitment in Australia
Recruitment state(s)
ACT,NSW,NT,QLD,SA,TAS,WA,VIC

Funding & Sponsors
Funding source category [1] 299890 0
Charities/Societies/Foundations
Name [1] 299890 0
Royal Life Saving Society – Australia
Address [1] 299890 0
Suite 6, Level 4, 173-179 Broadway (Cnr Mountain St), Broadway, NSW 2007
Country [1] 299890 0
Australia
Funding source category [2] 300134 0
University
Name [2] 300134 0
Menzies Health Institute Queensland
Address [2] 300134 0
Gold Coast campus, Griffith University, Cnr Parklands Drive and Olsen Avenue, Southport, QLD 4222
Country [2] 300134 0
Australia
Primary sponsor type
University
Name
School of Applied Psychology, Griffith University
Address
176 Messines Ridge Rd, Mt Gravatt, QLD 4122
Country
Australia
Secondary sponsor category [1] 299571 0
None
Name [1] 299571 0
None
Address [1] 299571 0
None
Country [1] 299571 0

Ethics approval
Ethics application status
Approved
Ethics committee name [1] 300759 0
Griffith University Human Research Ethics Committee
Ethics committee address [1] 300759 0
Nathan campus, Griffith University, 170 Kessels Rd, Nathan, QLD 4111
Ethics committee country [1] 300759 0
Australia
Date submitted for ethics approval [1] 300759 0
30/10/2017
Approval date [1] 300759 0
20/11/2017
Ethics approval number [1] 300759 0
2017/895

Summary
Brief summary
The current project will evaluate the effectiveness of a theory-based intervention utilising implementation imagery to reduce Australian drivers’ intentions to attempt to drive through floodwaters–a behaviour that carries significant risk of drowning. The aim is to develop an effective intervention that can be used as content by stakeholders with interests in drowning prevention to minimise risky driving behaviours and drowning risk.

Hypotheses
Hypothesis 1: We hypothesise that drivers assigned to the intervention condition will report significantly lower intentions to drive through floodwater, relative to the control condition immediately post-intervention at T2 (primary outcome).
Hypothesis 2: With regard to the secondary outcomes, we hypothesise that drivers assigned to the intervention condition will report significantly less favourable attitudes and reduced perceived social pressure to drive through floodwater, as well as greater perceptions of behavioural control, risk perception, perceived susceptibility, perceived severity, and anticipated regret toward driving through floodwater, relative to the control condition immediately post-intervention at T2.
Hypothesis 3: We further hypothesise that that drivers assigned to the intervention condition will report significantly greater barrier self-efficacy and action planning regarding avoiding driving through floodwater, relative to the control condition immediately post-intervention at T2.
Hypothesis 4: We also expect that the effects of the intervention will be maintained four-weeks later at T3.
Given our previous research has identified sex differences in changing beliefs (Hamilton, et al., 2018), we will also test for gender differences in the effects of the intervention on study outcomes.
Timepoints: Baseline (T1), immediately post-intervention (T2), 1-month follow-up post-intervention (T3).
Trial website
Trial related presentations / publications
Public notes

Contacts
Principal investigator
Name 84718 0
Dr Kyra Hamilton
Address 84718 0
School of Applied Psychology, Griffith University, Mt Gravatt Campus, 176 Messines Ridge Road, Mt Gravatt, QLD 4122
Country 84718 0
Australia
Phone 84718 0
+61737353334
Fax 84718 0
Email 84718 0
kyra.hamilton@griffith.edu.au
Contact person for public queries
Name 84719 0
Dr Kyra Hamilton
Address 84719 0
School of Applied Psychology, Griffith University, Mt Gravatt Campus, 176 Messines Ridge Road, Mt Gravatt, QLD 4122
Country 84719 0
Australia
Phone 84719 0
+61737353334
Fax 84719 0
Email 84719 0
kyra.hamilton@griffith.edu.au
Contact person for scientific queries
Name 84720 0
Dr Kyra Hamilton
Address 84720 0
School of Applied Psychology, Griffith University, Mt Gravatt Campus, 176 Messines Ridge Road, Mt Gravatt, QLD 4122
Country 84720 0
Australia
Phone 84720 0
+61737353334
Fax 84720 0
Email 84720 0
kyra.hamilton@griffith.edu.au

Data sharing statement
Will individual participant data (IPD) for this trial be available (including data dictionaries)?
Yes
What data in particular will be shared?
Deidentified raw participant data
When will data be available (start and end dates)?
Data will be made available immediately following publication of the trial and will remain available with no-end date.
Available to whom?
Anyone who wishes to access it
Available for what types of analyses?
Any purpose
By what mechanism will data be made available?
Data will be available with unrestricted access at: osf.io/z7xph/
What supporting documents are/will be available?
Study protocol
Statistical analysis plan
Informed consent form
Attachments/websites
Type [1] 293 0
URL/details/comments [1] 293 0
Study protocol will be published in a peer-reviewed journal article. Statistical analysis plan and informed consent form will be available within this article, which will be attached to this registration following publication.
Attachment [1] 293 0
Summary results
Have study results been published in a peer-reviewed journal?
No
Other publications
Have study results been made publicly available in another format?
Results – basic reporting
Results – plain English summary