Condition category
Nutritional, Metabolic, Endocrine
Date applied
21/07/2017
Date assigned
25/07/2017
Last edited
10/08/2017
Prospective/Retrospective
Retrospectively registered
Overall trial status
Ongoing
Recruitment status
No longer recruiting

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 measures

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

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 is 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

Sponsor information

Organisation

University of Cambridge

Sponsor details

Cambridge Research Office
16 Mill Lane
Cambridge
CB2 1SB
United Kingdom

Sponsor type

University/education

Website

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

01/04/2018

Participant level data

Not expected to be available

Results - basic reporting

Publication summary

Publication citations

Additional files

Editorial Notes

10/08/2017: Participant information sheet has been added