The Department of Health's interim evaluation of an alcohol industry pledge to remove one billion alcohol units from the market is flawed, argue researchers in The BMJ this week.
Dr John Holmes and colleagues at the University of Sheffield's Alcohol Research Group say key assumptions within the analysis are "simplistic" and call for the report to be withdrawn and revised targets set.
In 2012, the UK government announced an industry pledge to remove a billion units of alcohol from the market by December 2015, as part of the Public Health Responsibility Deal, the government's flagship public health policy.
The pledge would be achieved, it said, "principally through improving consumer choice of lower alcohol products."
In December 2014, the Department of Health produced its second interim report on progress towards meeting the pledge. It concluded that 1.3 billion units had been removed from the market as a result of the pledge between 2011 and 2013, exceeding the target two years early.
However, the research team argue that a closer look at the analyses and data that underpin this headline figure raises questions about how much of the recent changes in alcohol consumption are truly attributable to the pledge.
They believe the data used in the analysis "may not be fit for purpose, that the report makes simplistic assumptions about consumer responses to the pledge, and takes insufficient notice of confounding factors."
For example, they suggest a change to the way HM Revenue and Customs (HMRC) recorded beer data and the introduction of lower taxes on lower strength beers may account for some of the estimated effect of the pledge.
An assumption is also made in the analysis that the pledge will lead people to simply drink the same amount of beer and wine but at a lower strength. The researchers argue this is simplistic and means the analysis will give misleading results.
Until these problems of data, plausible consumer responses, and confounding have been addressed, the researchers say they question the validity of the conclusion that 1.3 billion units have been removed from the market or that the pledge has been met.
They acknowledge that their critique "does not imply the billion unit pledge is bad for public health" but they claim that a lack of appropriate data means a rigorous evaluation of whether the pledge has been met may not be possible.
They recommend that the Department of Health "withdraws the 2014 interim report, requests stakeholders not to cite its conclusions, and reviews the evaluation approach." They also recommend the billion unit target "is abandoned in favour of measurable alternatives."