Researching policy impacts

It is widely understood that policy-level interventions have had far greater effects on reducing tobacco use than individual-level measures. Yet, many continue to view the tobacco epidemic as a problem of individual decisions to use harmful products, rather than a problem of governments’ failure to properly protect the public from those unnecessary, addictive and lethal products in the first place. The papers in this e-issue consider the multiple impacts of policy changes and point to the importance of how those impacts are measured, as well as what we decide to measure and why it matters. The research-policy relationship, as noted by Warner and Tam in 2012,1 is a complicated and sometimes cyclical one in which research influences policy adoption, policy adoption changes the environment and policy impacts may turn out to be different than anticipated, opening up new research areas. Many policies remain unevaluated, and such evaluations, given the complexity of policy contexts, are highly challenging to do well, requiring consideration of multiple factors that may not always be obvious. The paper by Been et al 2 is illustrative. They used an interrupted time series design to assess the effects of Scottish implementation of a national smoke-free policy on children’s hospitalisations and deaths from respiratory infections. Using their prespecified model, they found a puzzling gradual increase in such hospitalisations. Post-hoc exploratory break point analyses demonstrated that the increase actually preceded the implementation of the law by 16 months. After accounting for this, the policy was found to be associated with a modest, gradual decrease in respiratory events. But health outcomes are not the only relevant measures of policy impact. Policy …