Summary
Within the field of public health, and increasingly across other areas of social policy, there
are widespread calls to increase or improve the use of evidence for policy making. Often
these calls rest on an assumption that improved evidence utilisation will be a more efficient
or effective means of achieving social goals. Yet, a clear elucidation of what can be
considered ‘good evidence’ for policy use is rarely articulated. Many of the current
discussions of best practice in the health policy sector derive from the evidence-based
medicine (EBM) movement, embracing the ‘hierarchy of evidence’ in framing the selection
of evidence – a hierarchy that places experimental trials as preeminent in terms of
methodological quality. However, there are a number of difficulties associated with applying
EBM methods of grading evidence onto policy making. Numerous public health authors
have noted that the hierarchy of evidence is a judgement of quality specifically developed
for measuring intervention effectiveness, and as such it cannot address other important
health policy considerations such as affordability, salience, or public acceptability (Petticrew
and Roberts, 2003).