Does size of wine glasses impact on restaurant wine sales? A replication study

ISRCTN	ISRCTN17097810
DOI	https://doi.org/10.1186/ISRCTN17097810
Secondary identifying numbers	RG58078

Submission date: 29/03/2018
Registration date: 17/04/2018
Last edited: 19/07/2019

Recruitment status: No longer recruiting
Overall study status: Completed
Condition category: Nutritional, Metabolic, Endocrine

Prospectively registered

Protocol

Statistical analysis plan

Results

Individual participant data

Plain English summary of protocol

Background and study aims:
Previous research has suggested that wine glass size might affect purchasing of wine in bars and restaurants, with larger glasses leading to more wine being purchased. The aim of the current study is to try to directly replicate an effect of glass size on purchasing, testing this effect in the same restaurant as in a previous study.

Who can participate?
This study takes place in one independent restaurant that has previously taken part in a similar study.

What does the study involve?
Depending on the study period, the size of the wine glass provided differs (being either 290ml, 350ml or 450ml). Portion sizes of wine are not altered. The study consists of thirteen periods, each lasting two weeks, starting in April 2018. In sequential order, the
restaurant offers: 290ml glasses; 350ml glasses; 290ml glasses; 450ml glasses; 290ml glasses; 350ml glasses; 290ml glasses; 450ml glasses; 290ml glasses; 350ml glasses; 290ml glasses; 450ml glasses; 290ml glasses. We examine the effect of glass size on the wine volume (in ml) sold per day in the restaurant.

What are the possible benefits and risks of participating?
The results from this study will help to establish the reproducibility and size of any effect of wine glass size on purchasing. Sales of wine may increase or decrease as a result of participating in the study.

Where is the study run from?
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?
February 2018 to December 2018

Who is funding the study?
Department for Health (UK)

Who is the main contact?
Dr Rachel Pechey (scientific)

Contact information

Dr Rachel Pechey
Scientific

Behaviour and Health Research Unit, Institute of Public Health, Forvie Site
Cambridge
CB2 0SR
United Kingdom

Study information

Study design	A multiple treatment reversal design will be used, to alter the size of wine glasses in one restaurant. The study will comprise thirteen sequential periods lasting two weeks: A (290ml glasses); B (350ml glasses); A (290ml glasses); C (450ml glasses); A (290ml glasses); B (350ml glasses); A (290ml glasses); C (450ml glasses); A (290ml glasses); B (350ml glasses); A (290ml glasses); C (450ml glasses); A (290ml glasses)
Primary study design	Other
Secondary study design
Study setting(s)	Other
Study type	Other
Participant information sheet	No participant information sheet available
Scientific title	Impact of wine glass size on restaurant wine sales: A replication study
Study objectives	The size of wine glasses used will alter wine sales in the restaurant, with: 1. 350ml wine glasses increasing sales compared with 290ml wine glasses 2. 450ml wine glasses increasing sales compared with 290ml wine glasses 3. 450ml wine glasses increasing sales compared with 350ml wine glasses
Ethics approval(s)	University of Cambridge Research Ethics Committee (Pre.2017.035), approved 9/5/17
Health condition(s) or problem(s) studied	Alcohol consumption
Intervention	The size of the wine glass in which all portions of wine served in the restaurant is altered over fortnightly periods. Portion size is not altered. Three different wine glass sizes is used: 290ml, 350ml or 450ml. The 350ml and 450ml is used for a total of 6 weeks each, while the 290ml reference glass is used for a total of 14 weeks. The study comprises thirteen sequential periods lasting two weeks (i.e. 26 weeks in total): A (290ml glasses); B (350ml glasses); A (290ml glasses); C (450ml glasses); A (290ml glasses); B (350ml glasses); A (290ml glasses); C (450ml glasses); A (290ml glasses); B (350ml glasses); A (290ml glasses); C (450ml glasses); A (290ml glasses).
Intervention type	Behavioural
Primary outcome measure	Daily volume (ml) of wine purchased throughout the 26 weeks of the study is obtained from the restaurant’s till records
Secondary outcome measures	None planned
Overall study start date	01/02/2018
Completion date	31/12/2018

Eligibility

Participant type(s)	Other
Age group	Adult
Sex	Both
Target number of participants	One independent restaurant
Key inclusion criteria	One restaurant in Cambridge, UK, that has previously participated in a study following the same study design
Key exclusion criteria	N/A
Date of first enrolment	01/03/2018
Date of final enrolment	31/03/2018

Locations

Countries of recruitment

England
United Kingdom

Study participating centre

Behaviour and Health Research Unit

University of Cambridge
Cambridge
CB2 0SR
United Kingdom

Sponsor information

University of Cambridge
University/education

16 Mill Lane
Cambridge
CB2 1SB
England
United Kingdom

"ROR"	https://ror.org/013meh722

Funders

Funder type

Not defined

Department of Health Policy Research Programme (Policy Research Unit in Behaviour and Health [PR-UN-0409-10109])

No information available

Results and Publications

Intention to publish date	01/09/2019
Individual participant data (IPD) Intention to share	No
IPD sharing plan summary	Not expected to be made available
Publication and dissemination plan	1. Planned submission of the main results of this study for publication in peer-reviewed journal 2. Presentation of results at academic conferences 3. Dissemination of the results to the public, policy makers and other researchers through targeted social media
IPD sharing plan	The datasets generated during and/or analysed during the current study are not expected to be made available because they are commercially sensitive and provided on condition that they are not shared beyond the research team

Study outputs

Output type	Details	Date created	Date added	Peer reviewed?	Patient-facing?
Results article	results	17/07/2019	19/07/2019	Yes	No

Editorial Notes

19/07/2019: Publication reference added.