Plain English Summary
Background and study aims
Excessive alcohol consumption amongst youths, especially students, poses serious health and risk problems. Research suggests that the serving-size of glasses in which alcohol is consumed may influence both the amounts poured, perceptions of portion size, drinking pace as well as purchasing and consumption behaviour. The aim of this study is to examine the impact of reducing the standard serving size, including size of glass, of beer by 20% on on-site beer consumption by students in a student bar.
Who can participate?
Guests at a large student dormitory bar in Copenhagen, Denmark
What does the study involve?
Beer glasses of two different sizes are placed in a random sequence under the bar desk. The students are either served free beer with a standard 50 cl serving size or a smaller 40 cl serving size during the first 2.5 hours of the student event. Consumption is measured by writing the students’ names on their glasses and then videotaping the glasses served from cameras placed underneath the bar desk and monitoring the students throughout the night.
What are the possible benefits and risks of participating?
The possible benefits and risks are that participants might get tipsy.
Where is the study run from?
Roskilde University (Denmark)
When is the study starting and how long is it expected to run for?
The study took place in April 2017
Who is funding the study?
Investigator initiated and funded
Who is the main contact?
Pelle Guldborg Hansen
Does the serving-size of beer glasses matter for how much students drink on a night out? A randomised controlled field experiment
This experiment aimed to examine the impact of reducing the standard serving-size, including size of glass, of beer with 20% on on-site beer consumption by students in a student bar. The hypothesis was that the intervention would lead to a reduction.
Approved 25/05/2020, The Committee for Research Ethics, Roskilde University (Institute for Communication Studies and Arts, Roskilde University, Universitetsvej 1, Bld. 42.1, 4000 Roskilde, Denmark; +45 (0)4674 2445; Ryberg@ruc.dk), no ref. number
Randomised controlled field experiment
Primary study design
Secondary study design
Randomised controlled trial
Patient information sheet
Excessive alcohol consumption
At a regular quiz night in a large student dormitory bar in Copenhagen, Denmark, beer glasses of two different sizes are placed in a randomised sequence under the bar desk. This allowed for randomly allocating the 103 participating students into two groups either served free beer with standard 50 cl serving size (n = 54) or smaller 40 cl serving size (n = 49) during the first 2.5 hours of the student event. Consumption is measured by writing the students’ names on their glasses and then videotaping the glasses served from cameras placed underneath the bar desk and monitoring the students throughout the night.
Primary outcome measure
Beer served measured in centiliters by having bartenders pour beer to a particular line on the beer glasses and recording this with go-pro cameras during the first 2.5 hours of the student event
Secondary outcome measures
There are no secondary outcome measures
Overall trial start date
Overall trial end date
Reason abandoned (if study stopped)
Participant inclusion criteria
Guests at a dormitory bar
Target number of participants
Total final enrolment
Participant exclusion criteria
Does not meet inclusion criteria
Recruitment start date
Recruitment end date
Countries of recruitment
Trial participating centre
Investigator initiated and funded
Funding Body Type
Funding Body Subtype
Results and Publications
Publication and dissemination plan
Intended to be published in BMC Public Health.
IPD sharing statement
The datasets generated during and/or analysed during the current study are/will be available upon request from Pelle Guldborg Hansen (email@example.com). Type of dataset: Excel. The data will be available as long as required conditional on an academic affiliation as a full-time researcher for all types of analyses. No need for consent from participants will be needed as the data is fully anonymised.
Intention to publish date
Participant level data
Available on request
Basic results (scientific)