Plain English Summary
Background and study aims
Alcohol consumption is a major cause of disease. Sometimes drinkers are unaware of how much they are being served and how much they consume. Previous research has suggested that the size of wine glasses might affect purchasing of wine, with larger glasses leading to more purchases. The aim of the current study is to try to replicate this previous work and establish the reliability of any effect of glass size on purchasing.
Who can participate?
One independent restaurant in Cambridge UK is participating in the study. Data will be based on customers visiting the restaurant during the 18-week study period.
What does the study involve?
The restaurant provides different glass sizes to customers who order wine based off a schedule. First, they introduce medium-size wine glasses (29cl glasses) in the restaurant for a period of two weeks. The portion sizes of wine sold is not changed (the restaurant continues to sell wine by the glass (125ml and 175ml portions) and by the bottle. All portion sizes are served in the same wine glass. We then change to a larger (35cl) wine glass for the next two weeks. The medium-size wine glass is then used again for two weeks. For weeks seven to eight smaller (23cl) glasses are used. Then this pattern is repeated again (i.e. medium-size, larger, medium-size, smaller), and then the study finishes with a final two week period where the medium-size glasses are used again. The sales of wine when using the medium-size glasses to sales when using each of the larger and smaller glass sizes are compared.
What are the possible benefits and risks of participating?
There are no benefits or risks with participating.
Where is the study run from?
Testing will take place in one independent 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?
April 2017 to December 2017
Who is funding the study?
Department of Health Policy Research Programme (Policy Research Unit in Behavior and Health) (UK)
Who is the main contact?
Dr Rachel Pechey
Trial website
Contact information
Type
Scientific
Primary contact
Dr Rachel Pechey
ORCID ID
http://orcid.org/0000-0002-6558-388X
Contact details
Behaviour and Health Research Unit
Institute of Public Health
University of Cambridge
Cambridge
CB2 0SR
United Kingdom
Additional identifiers
EudraCT number
ClinicalTrials.gov number
Protocol/serial number
N/A
Study information
Scientific title
The impact of wine glass size on wine sales: a replication study in a restaurant setting
Acronym
Study hypothesis
Changing the size of wine glasses will alter wine sales in the restaurant, with larger wine glasses increasing sales.
Ethics approval
University of Cambridge Research Ethics Committee, 09/05/2017, ref: Pre.2017.035
Study design
Multiple treatment reversal design, whereby one restaurant changes the size of glasses used with wine purchases every fortnight for an 18-week period
Primary study design
Interventional
Secondary study design
Multiple treatment reversal design
Trial setting
Other
Trial type
Prevention
Patient information sheet
See additional files
Condition
Alcohol consumption
Intervention
The restaurant is the participant in this study. Customers at the restaurant are unaware of the intervention. When they order wine, they receive the portion ordered as usual, but this portion is served in a wine glass that is smaller, medium-size or larger, depending on the week of the study.
The restaurant's usual glasses are replaced with different-sized glasses (of the same glass design). Glasses will have smaller (23cl), medium (29cl) or larger (35cl) capacity.
Glasses will be changed fortnightly, over an 18-week period, as per the following schedule:
A: Medium-sized (290ml) glass
B: Larger (350ml) glass
A: Medium-sized (290ml) glass
C: Smaller (230ml) glass
A: Medium-sized (290ml) glass
B: Larger (350ml) glass
A: Medium-sized (290ml) glass
C: Smaller (230ml) glass
A: Medium-sized (290ml) glass
There will be no follow up with customers (The change in glasses is not expected to raise any issues for customers. As well as potentially causing issues for the study design, obtaining consent (and debriefing) would interfere with the procedures for serving customers in participating venues.)
Intervention type
Behavioural
Phase
Drug names
Primary outcome measure
The daily volume (ml) of wine purchased throughout the 18 weeks of the study, obtained from the till records of the restaurant
Secondary outcome measures
There are no secondary outcome measures.
Overall trial start date
01/04/2017
Overall trial end date
31/12/2017
Reason abandoned (if study stopped)
Eligibility
Participant inclusion criteria
UK restaurants serving wine
Participant type
Other
Age group
Other
Gender
Both
Target number of participants
One independent restaurant
Participant exclusion criteria
There are no exclusion criteria
Recruitment start date
07/07/2017
Recruitment end date
01/08/2017
Locations
Countries of recruitment
United Kingdom
Trial participating centre
Behaviour and Health Research Unit
Institute of Public Health
University of Cambridge
Cambridge
CB2 0SR
United Kingdom
Funders
Funder type
Government
Funder name
Department of Health Policy Research Programme (England)
Alternative name(s)
Funding Body Type
Funding Body Subtype
Location
Results and Publications
Publication and dissemination plan
This study has been pre-registered on the Open Science Framework (https://osf.io/sekmt/), further information is available there. Intention to write up the study for publication in early 2018.
IPD sharing statement:
The datasets generated during and/or analysed during the current study is not expected to be made available as the datatset will comprise sales data from one restaurant, which is commercially sensitive.
Intention to publish date
01/04/2019
Participant level data
Not expected to be available
Basic results (scientific)
Publication list
2019 results in: https://www.ncbi.nlm.nih.gov/pubmed/31315655 (added 19/07/2019)
Publication citations
Additional files
- ISRCTN17958895_PIS_24Jul17.pdf Uploaded 10/08/2017