Young people often consume alcohol at home before a night out. Alcohol is much cheaper from off-licences and supermarkets and drink brought in this way makes up an increasing proportion of total alcohol sales. A study of 380 young people in the North West of England asked them whether they drank before they went out, how much alcohol they drank and whether they had had bad experiences on a night out. The study found that over a quarter (26.5%) of female and 15.4% of male alcohol consumption occured before going out. Those who drank before going out drank significantly more alcohol, were four times as likely to drink 20 or more units of alcohol and 2.5 times as likely to have been involved in a fight in the last year.
Hughes, Karen ... [et al] - Alchohol, nightlife and violence : the relative contributions of drinking before and during nights out to negative health and criminal justice outcomes Addiction 103(1), 60-65