A cross-sectional opportunistic (non-random) survey on alcohol consumption and access to alcohol was conducted in 2007 in schools amongst 14 to 17 year olds  by Trading Standards North West (a Government body who uphold trading regulations) in the North West of England, a region with significantly high levels of alcohol misuse compared with elsewhere in England . The survey used closed self-completion questions covering a number of topics. Firstly, in order to understand the characteristics and experiences of those involved in risky behaviours, questions included: demographics; personal weekly income of the young person (for example, from pocket money and money received through employment); drinking frequencies; and quantities of alcohol consumed in a typical week. Details of drinking frequencies and quantities were used to inform the following categories: binge drinking (drinking five or more alcoholic drinks on one occasion at least once a week, a definition used to describe binge drinking in 15-16 year olds in large-scale European survey[25, 26]) and frequent drinking (drinking at least twice a week). Whether the participant drank in public places was also included (drinking outside in streets, around shops and in parks) as a measure of the potential for social nuisance. To understand experiences of purchasing and access, participants were asked details of their sources of alcohol; whether they had been asked for identification when attempting to buy alcohol; and if they had used fake identification. Finally, participants were also asked questions regarding their experiences of alcohol-related harm in order to understand whether those who owned fake identification were more at risk of experiencing such incidents. Harms listed on the questionnaire (one question for each harm) related to: entering a car with a drunk driver; violence when drunk; regretted sex and memory lapses (episodes where the individual did not remember past events after drinking). The first three harms were binary questions, where the participant could select yes or no. Data on memory lapses were collected via a four point ordinal Likert scale (agree strongly, agree, disagree, disagree strongly) asking whether individuals felt that they tended to forget things after drinking, which was then categorised into those who agreed that they tended to forget about drinking and those who did not.
The survey was anonymous and was made available for schools in the North West to participate voluntarily through local Trading Standards services. No incentive was offered for participation. Sampling was intended to encompass a wide range of community types. Participating schools allowed pupils to voluntarily complete the questionnaires during normal school lessons. All aspects of the methodology complied with the Declaration of Helsinki and consent was provided through the regional trading standards board and participating schools. In total, 140 schools in 19 unitary and upper tier local authorities took part in the survey (out of 22 such authorities in the North West region), returning 11,724 questionnaires. Compliance levels were not recorded because the sample was intended to be opportunistic, with analysis focusing on relationships between variables that were recorded by individual participants. Analyses were limited to 15-16 year olds, the largest age group surveyed, providing an analysed sample of 9,833.
Data were entered by Ci Research into SPSS v14, and then cleaned and analysed by Liverpool John Moores University (SPSS v17). Deprivation was allocated according to the Index of Multiple Deprivation (IMD)[24, 28] for their resident Lower Super Output Area (geographical areas with an average population size of approximately 1,500 individuals). (IMD is a national measure and is calculated through the use of factors such as income, employment, skills and training, and barriers to housing. Allocated scores are then assigned to super output areas). We assigned IMD scores through either their full (n = 4,158) or partial postcode (n = 1,744) where provided. For those without a postcode (n = 2,063), the postcode of their school was used as a proxy, a method employed successfully elsewhere . (Here, a strong correlation was identified between deprivation scores derived from our sample's postcodes with those derived from that of the school; P < 0.001). Individuals who provided insufficient data (n = 298) were excluded from geographic analyses. The scores were then categorised into IMD quintiles. Participants' income was calculated through the use of three questions asking for details of amounts of money obtained from parents, work and other sources. We totalled the sums provided.
Analysis incorporated chi square and logistic regression techniques. Logistic regression was used firstly to estimate the likelihood of ownership of fake identification (from sex, age, deprivation and personal weekly income), and secondly to assess the importance of owning fake identification in relation to experiences of harmful consumption patterns (controlling for demographic characteristics).