Plain English Summary
Background and study aims.
Previous research has suggested that people’s perceptions of the portion size of wine are influenced by the size of the wine glass (with the same given volume of wine perceived as less in larger glasses than in smaller glasses), but it is not clear whether glass size can also affect the amount of wine that is purchased or consumed. The aim of the current study is to examine the impact of the size of wine glasses on wine purchasing, and in particular to test the hypothesis that sales of wine will decrease with decreasing wine glass size.
Who can participate?
One independent bar/restaurant in Cambridge UK is participating in the study. Data will be based on customers visiting the restaurant during the 10-week study period.
What does the study involve?
At one independent bar/restaurant, we first replace the standard wine glasses (30 cl glasses) used with larger (37 cl) for a period of two weeks. The standard size wine glass is then used again for the next two weeks. From week 6 to 8 smaller (25 cl) glasses are used. Finally, the standard wine glasses are used for the last two weeks of the study. We compare sales of wine at the beginning of the study with sales when using each glass size.
What are the possible benefits and risks of participating?
We consider this study to be low risk. We do not expect any adverse consequences associated with taking part in the study. The findings from this study will generate preliminary evidence of the impact of the size of wine glasses on purchasing of wine.
Where is the study run from?
Testing will take place in one independent bar/restaurant in Cambridge (UK). The study is run from the Behaviour and Health Research Unit at the University of Cambridge (UK).
When is the study starting and how long is it expected to run for?
March 2015 to June 2015.
Who is funding the study?
Department of Health Policy Research Programme (Policy Research Unit in Behavior and Health [PR-UN-0409-10109])
Who is the main contact?
Professor Theresa Marteau
tm388@cam.ac.uk
Trial website
Contact information
Type
Scientific
Primary contact
Dr Theresa Marteau
ORCID ID
Contact details
Behaviour and Health Research Unit
University of Cambridge
Institute of Public Health
Forvie Site
Cambridge
CB2 0SR
United Kingdom
+44 (0)1223 330331
tm388@cam.ac.uk
Additional identifiers
EudraCT number
ClinicalTrials.gov number
Protocol/serial number
N/A
Study information
Scientific title
Does size of wine glasses impact on on-licence sales? An experimental study using a multiple treatment reversal design.
Acronym
Study hypothesis
The impact on purchasing and consumption of altering the size of glasses in which alcohol is served is uncertain. The aim of the current study is to examine the impact of the size of wine glasses on wine purchasing, and in particular, to test the hypothesis that sales of wine will decrease with decreasing wine glass size. The specific study hypothesis is: Sales of wine when using 37 cl glasses will be higher than sales of wine when using 30 cl glasses, which will be higher than sales of wine when using 25 cl glasses
Ethics approval
University of Cambridge Psychology Research Ethics Committee, 27/01/2015, ref: Pre.2014.127
Study design
The study will use a multiple treatment reversal design, conducted in an outlet that functions as both a bar and restaurant, with each of five periods lasting two weeks:
A: Baseline: standard 30 cl glass in use
B: Larger 37 cl glass to replace standard glass
A: Standard 30 cl glass in use
C: Smaller 25 cl glass to replace standard glass
A: Standard 30 cl glass in use
20/10/2015: Following discussion with the participating outlet, the decision was taken to extend the study so as to have two fortnightly periods where each of the intervention glasses were used, i.e. eight periods lasting two weeks:
A: Baseline: standard 30 cl glass in use
B: Larger 37 cl glass to replace standard glass
A: Standard 30 cl glass in use
C: Smaller 25 cl glass to replace standard glass
B: Larger 37 cl glass to replace standard glass
A: Standard 30 cl glass in use
C: Smaller 25 cl glass to replace standard glass
A: Standard 30 cl glass in use
Primary study design
Interventional
Secondary study design
Multiple treatment reversal design
Trial setting
Community
Trial type
Prevention
Patient information sheet
Condition
Alcohol consumption, which is ranked 5th amongst the 20 leading risk factors for burden of disease in the UK.
Intervention
Replacing the wine glasses used in an outlet selling wine to compare baseline sales of wine (i.e. when using the outlet’s standard glasses) to sales when using larger and smaller glasses.
The current standard glasses used in the target outlet have a capacity of 30cl. The replacements are:
1. Smaller: 25cl glass, of same design as the standard glass
2. Larger: 37cl glass of same design as the standard glass
Each replacement will last two weeks and will be interceded by a two-week return to use of the outlet’s standard glasses.
Intervention type
Behavioural
Phase
Drug names
Primary outcome measures
The daily volume of wine purchased in each intervention period compared to baseline.
Secondary outcome measures
N/A
Overall trial start date
15/03/2015
Overall trial end date
30/09/2015
Reason abandoned
Eligibility
Participant inclusion criteria
English outlets serving wine
Participant type
Other
Age group
Not Specified
Gender
Not Specified
Target number of participants
One independent bar/restaurant in Cambridge, UK is participating in the study. Data will be based on purchases made by thousands of customers (18 years and over) visiting the restaurant during the study period and ordering wine.
Participant exclusion criteria
N/A
Recruitment start date
15/03/2015
Recruitment end date
30/06/2015
Locations
Countries of recruitment
United Kingdom
Trial participating centre
Behaviour and Health Research Unit
University of Cambridge
Institute of Public Health
Forvie Site
Cambridge
CB2 0SR
United Kingdom
Funders
Funder type
Government
Funder name
Department of Health Policy Research Programme (UK)
Alternative name(s)
Funding Body Type
Funding Body Subtype
Location
Results and Publications
Publication and dissemination plan
We plan and write up our findings and submitting them to a scientific journal for peer review and publication. The expected date for this is August 2015.
Intention to publish date
Participant level data
Not expected to be available
Results - basic reporting
Publication summary
2016 results in: http://www.ncbi.nlm.nih.gov/pubmed/27268112