Re: https://www.hifa.org/dgroups-rss/steve-hanney-introduction-and-role-impa...
Dear Steve,
Many thanks for joining HIFA and continuing our discussion here.
"That led to the iteration with Neil, in which I suggested that while evidence syntheses clearly play a very important role in providing rigorous health information, impact assessments have identified various contexts in which single studies, or programmes, have made an identifiable and important impact on policies/decisions. Perhaps the most common form of impact on policies is the direct citation of a primary study on a clinical guideline."
Yes, I think nevertheless the adoption of rigorous synthesis and systematic reviews (from the early 1990s) has been perhaps the greatest conceptual leap forward since the introduction of randomised controlled trials in the 1940s. Before the 90s, WHO guidelines were undertaken by a group of experts, using individual studies (and sometimes personal experience) to support their personal opinions. WHO's methods now centre on rigorous evidence synthesis and WHO guidelines are among its most trusted and important outputs. Evidence synthesis is one of the six key components of the global evidence ecosystem www.hifa.org/ecosystem
I agree that individual studies can also have a direct impact. In some situations this is appropriate. For example, the randomised controlled trial ISIS-2 Aspirin for acute myocardial infarction trial (1988–1991) found such a clear benefit that policy was changed almost overnight. Even here, it is generally better to systematically assess all available studies.
A big gap in capacity that we have recognised repeatedly on HIFA is the ability of countries to develop national policy, drawing on international guidance from WHO and taking into account relevant national/local research and context. I would be very interested to learn more from you and others about this process. To what extent is it feasible, and how, especially in LMICs? How can countries be better supported, for example by improving the usability of international guidance or by national policymaking tools and capacity-building?
Whether or not to accept the findings of a single research study depends also on the type of research. For example, perhaps it is often appropriate to adopt single studies in health systems research at country level, especially where these are designed to help inform a particular policy direction? Is there a role for subanalyses of systemtic reviews, perhaps focusing on studies from LMICs or with certain characteristics?
There is also a potential concern whereby a single study might have more impact on policy or practice than it should do, not because of the inherent value of the research but because the proponents of that particular study are able to 'shout' louder than other researchers. We all assume that researchers need to be communicators (to inform? to persuade?) but I see there can also be a downside to 'effective' communication.
Best wishes, Neil
HIFA profile: Neil Pakenham-Walsh is coordinator of HIFA (Healthcare Information For All), a global health community that brings all stakeholders together around the shared goal of universal access to reliable healthcare information. HIFA has 20,000 members in 180 countries, interacting in four languages and representing all parts of the global evidence ecosystem. HIFA is administered by Global Healthcare Information Network, a UK-based nonprofit in official relations with the World Health Organization. Email: neil@hifa.org