Evidence based policy or policy based evidence?

This short editorial ask whether a policy maker's willingness to take action influences the view of the evidence from researchers.

As an example, it looks at UK attitudes to recent research on the control of alcohol. Two reports were published in the UK in March 2004:

• by the Academy of Medical Sciences: the academy's report concluded that to control alcohol problems one needed to control alcohol; that is, reduce the average level of consumption in the population. The academy reached this conclusion on the basis that a strong correlation exists between average consumption, the prevalence of heavy drinking, and associated harm. It found the evidence for education unconvincing and therefore called for raising the price and limiting availability.
• by the Prime Minister's Strategy Unit: with access to the same evidence, the unit concluded that controlling average consumption through the mechanism of raising the price and limiting access would have unwanted side effects and was not a viable option. They therefore called for education, more policing, improved treatment, and the alcohol industry entering into voluntary agreements to behave reasonably.

The two reports, using the same evidence, came to different conclusions. The academy's report was based on one set of prejudices, the strategy unit had a different set: perhaps finding the prospect of raising the tax on alcohol, or making it more difficult to buy, unattractive.

In this case, the policy implications of the science may well have influenced the view of the evidence, suggesting a separation of two issues: what the science shows and its policy implications. It is perfectly reasonable for governments to balance a number of interests in forming policies. Scientific evidence on dose response relations between exposure and risk is only one consideration. Others include analysis of costs and benefits, risk analysis, and appreciation of the degree to which policies fit with public values. It is helpful, however, to keep these distinct. [adapted from author]