The research, published in the BioMed Central journal, attracted national headlines, despite it already known that self-reported consumption typically gives a figure 40% lower than HMRC sales data. However the new study still only accounts for some of the under-reporting, with a number of possible factors for further 'missing' units. The role of storage, spillage, under 16's consumption and tourist consumption are hard to gauge for example.
The study highlights a number of flaws with current national survey approaches which focus on typical or average drinking in the last week. As one of the authors, James Nicholls from Alcohol Research UK, highlights in a supporting BioMed blog: 'drinking, while often routine, is more usually a matter of peaks and troughs, in which periods of fairly low consumption are interspersed with episodes – Christmas, for example – where our drinking shoots up.'
Differences between groups were also found, for instance the most missed units were found amongst 25 to 34 year-olds who have the highest typical consumption; atypical or special occasions added approximately 18 units a week (144g) for men and women of this age. A BBC report said the amount under-reported across all groups was equivalent to more than three-quarters of a bottle of wine per drinker every week
In a Guardian report, lead author Mark Bellis of Bangor and John Moores universities, highlighted that 'summer holidays, bank holidays, weddings and many other special occasions' as times where true alcohol consumption is overlooked in most survey data. See the behind the headlines analysis here.
The research team conclude that 'the additional units are inevitably linked to increases in lifetime risk of alcohol-related disease and injury, particularly as special occasions often constitute heavy drinking episodes.' Critics may argue - perhaps simplistically - tell us what we don't already know; researchers say further understanding of true consumption and associated patterns help better inform public health interventions.