How to frame swaps within an online supermarket platform to maximise acceptance rates: comparing health, social norms and cost framed messages
| ISRCTN | ISRCTN67116897 |
|---|---|
| DOI | https://doi.org/10.1186/ISRCTN67116897 |
| Secondary identifying numbers | N/A |
- Submission date
- 30/09/2015
- Registration date
- 30/09/2015
- Last edited
- 12/05/2021
- Recruitment status
- No longer recruiting
- Overall study status
- Completed
- Condition category
- Nutritional, Metabolic, Endocrine
Plain English summary of protocol
Background and study aims
Prompting people with healthier alternative foods is a simple way to shift people towards buying healthier food, and has been used in a number of healthy eating campaigns. Recent work has explored the impact of offering automatically-selected lower-calorie swaps on an experimental supermarket website. This study found no overall effects of swaps, due to participants often not accepting the swaps or accepting swaps with a smaller reduction in calories. Those people who accepted more swaps did show reductions in the calories of their purchases. The current study aims to extend this work by testing whether framing the swap without appealing to health, instead using cost or social norms, might improve swap acceptance, and the impact of combining two of these frames.
Who can participate?
People aged 18-80 who are responsible for “about half” or “all or most” of the food/grocery shopping.
What does the study involve?
All participants are asked to shop for 10 items in an online supermarket shopping situation using an experimental website. At the end of the shopping task participants are presented with swaps offering healthier food choices, which are also cheaper than the initially selected item. Participants are randomly allocated to one of three groups, with each group using one of the following three phrases to offer the swaps:
1. “Swap to save calories”
2. “Swap to save money”
3. “Swap to this product chosen by customers who buy similar groceries to you”
What are the possible benefits and risks of participating?
Participants are unlikely to gain or lose anything from participating in the study.
Where is the study run from?
Behaviour and Health Research Unit, Cambridge University (UK).
When is study starting and how long is it expected to run for?
The study will run for 1 week in October 2015.
Who is funding the study?
Public Health England (UK).
Who is the main contact?
Anna Sallis
anna.sallis@phe.gov.uk
Contact information
Scientific
80 London Road
London
SE1 6LH
United Kingdom
Study information
| Study design | Three-arm randomised controlled trial |
|---|---|
| Primary study design | Interventional |
| Secondary study design | Randomised controlled trial |
| Study setting(s) | Internet/virtual |
| Study type | Other |
| Scientific title | Message framing for uptake of within-category healthy food swaps: an experimental online supermarket study across socio-economic groups |
| Study objectives | 1. Swaps framed in terms of the cost benefit or social norms are more likely to be accepted than swaps framed in terms of health benefit 2. Swaps framed in terms of cost are more accepted by individuals in low socioeconomic status (SES) groups whereas swaps framed in terms of health are more accepted by those in high SES groups |
| Ethics approval(s) | Cambridge Psychology Research ethics committee, 03/09/2015, PRE 2015 056 |
| Health condition(s) or problem(s) studied | Online supermarket shopping |
| Intervention | The study will follow a between-subjects experimental design with three arms, assessing the impact of swap framing on swap acceptance. The effects will be compared with a simple health framing control. All participants are randomly allocated to one of three conditions. Groups will differ in the wording used at the top of the swap window. 1. Swap framed in terms of health alone (control): “Swap to save calories” 2. Swap framed in terms of cost alone: “Swap to save money” 3. Swap framed in terms of social norm alone: “Swap to this product chosen by customers who buy similar groceries to you” |
| Intervention type | Behavioural |
| Primary outcome measure | Proportion accepted swaps: number of swaps accepted, number of swaps offered |
| Secondary outcome measures | 1. Energy density (kJ per 100g) of the basket of goods purchased and the basket of original goods chosen, i.e. had swaps not been offered 2. Nutrient content of basket of goods purchased and of basket of original goods chosen including saturated fat, total sugar and salt 3. Acceptability of intervention – measured after completion of shopping. 4. Age 5. Gender 6. Self-reported weight 7. Self–reported height 8. SES: individual level – both highest educational qualification (UK census levels) and household income |
| Overall study start date | 01/10/2015 |
| Completion date | 31/10/2015 |
Eligibility
| Participant type(s) | Healthy volunteer |
|---|---|
| Age group | Adult |
| Lower age limit | 18 Years |
| Sex | Both |
| Target number of participants | 900 |
| Total final enrolment | 900 |
| Key inclusion criteria | Participants will be recruited via a research agency and will cover a spread of socio-economic status ABC1 (53%), C2DE (47%), gender (50:50) and age (18 to 80). Screening questions will be used to ensure all participants are responsible for “about half” or “all or most” of the food/grocery shopping (UK national surveys indicate this to be the case for 73% of the population (Food Standards Agency, 2011)). |
| Key exclusion criteria | Participants who are not responsible for “about half” or “all or most” of the food/grocery shopping |
| Date of first enrolment | 01/10/2015 |
| Date of final enrolment | 08/10/2015 |
Locations
Countries of recruitment
- England
- United Kingdom
Study participating centres
United Kingdom
United Kingdom
Sponsor information
Government
80 London Road
London
SE1 6LH
United Kingdom
Funders
Funder type
Government
Government organisation / National government
- Alternative name(s)
- PHE
- Location
- United Kingdom
Results and Publications
| Intention to publish date | 30/03/2016 |
|---|---|
| Individual participant data (IPD) Intention to share | No |
| IPD sharing plan summary | Not expected to be made available |
| Publication and dissemination plan | Conferences and academic journals |
| IPD sharing plan |
Study outputs
| Output type | Details | Date created | Date added | Peer reviewed? | Patient-facing? |
|---|---|---|---|---|---|
| Results article | 17/02/2021 | 12/05/2021 | Yes | No |
Editorial Notes
12/05/2021: The following changes have been made:
1. Publication reference added.
2. The final enrolment number has been added from the reference.
19/01/2018: No publications found in PubMed, verifying study status with principal investigator.
