Improving Population Health: The Uses of Systematic Reviews

Topic:
Population Health

Executive Summary

Efforts to improve population health will yield better returns if there is more effective integration of reliable scientific evidence into policymaking. Increasing the use and usefulness of systematic reviews is one powerful mechanism for improving the evidence available to inform population health decision making.

Systematic reviews provide a systematic, transparent means for gathering, synthesizing, and appraising the findings of studies on a particular topic or question. They aim to minimize the bias associated with single studies and nonsystematic reviews. They can include many types of studies from diverse disciplines.

Systematic reviews can help provide information useful to policymakers, practitioners, and researchers, including the extent of a health problem and whether interventions work, at what cost, and for whom. They can help policymakers make the most efficient use of scarce resources and evaluate the relative merits of competing policies or programs—though for the most part current reviews compare an innovative intervention with some sort of “usual care” scenario rather than
compare two different interventions or strategies. Systematic reviews can also help policymakers resist pressures from vested or competing interests, and they can help identify gaps in the evidence and priorities for future research.

Population health is affected by policymaking in many areas, including both government and nongovernment enterprises, as well as sectors other than health. Therefore, a broad perspective should be taken in considering the scope of systematic reviews and their potential users. In this report, policymakers are considered to include public and private sector organizations whose decisions influence health, whether they sit in the health sector or elsewhere.

Moves are under way to improve policymakers’ access to and use of relevant, reliable information from systematic reviews. However, scientific evidence is only one of many forces and many types of information that influence policymaking. Systematic reviews face tough competition for policymakers’ attention. They cannot always provide information that is useful or relevant to policymakers’ needs, and policymakers often must make decisions on the basis of incomplete evidence within a very short time frame.

Evidence-based public/population health differs from evidence-based medicine because it bridges complex systems and populations rather than homogenous patient populations. Many methodological issues confront those who produce and use systematic reviews relevant to public/population health, and concerted efforts are under way to improve the quality of systematic reviews in this area. David MacLean, professor and dean of the faculty of health sciences at Simon Fraser University in British Columbia, has expressed concerns that overreliance on systematic reviews or unquestioning use of them might stifle creativity and innovation or lead to useful programs being sidelined because of their inadequate evidence base.

This report includes case studies—ranging from tobacco control to binge drinking among college students to the mental health challenges of the Indian Ocean tsunami—that bear many lessons for those seeking to improve population health. First and foremost they suggest there is significant room to enhance the role of evidence in policymaking. They also reveal the importance of

  •  taking a systems, environmental, or policy approach to changing human behavior, rather than strategies focused solely on individuals,
  • the role of social norms in influencing behavior,
  • the power of legislative, regulatory, and financial incentives to encourage the implementation of evidence-based policies, and
  • the value of a reliable and relevant evidence base to help set political and public agendas and to shape interventions.

These themes are also instructive for those seeking to boost the role of evidence in population health decision making. Improving the use and usefulness of systematic reviews will require individual researchers, policymakers, advocates, and other relevant groups to modify the way they work. Success in this endeavor is most likely to be achieved if systemic, environmental, and cultural changes promote and support them.

As the case studies demonstrate, the real-world interaction between evidence and action is complex, and while each serves to improve the other over time, the ease and speed of this process can be improved. The case studies also highlight the importance of fearless and prominent champions in influencing political and professional agendas. They show the value of collaboration, perseverance, and pragmatism.

Those who seek to improve the use and usefulness of systematic reviews must recognize that policymaking is not a linear process and that a comprehensive array of interventions is more likely to have an impact than any single intervention. They must also be systematic by making deliberate, strategic efforts to disseminate and implement review findings, as well as ready and willing to seize moments of opportunity. Timeliness is often crucial in the policy environment.

This report makes recommendations for a comprehensive range of strategies, involving researchers, policymakers, the media, interest groups, and the broader community, in order to make systematic reviews both more useful and utilized. Recommendations include organizational and cultural changes to improve the translation and dissemination of systematic reviews; collaboration across sectors and disciplines to improve the quality, timeliness, accessibility, and relevance of
systematic reviews; and incentives to encourage researchers, policymakers, and interest groups to work towards better integration of evidence into policy.

The importance of the media should not be overlooked. Just as effective media advocacy contributed to many of the public health advances outlined in this report, so can it contribute to efforts to promote both demand for and supply of useful, relevant systematic reviews. Media advocacy has been defined as the “strategic use of mass media to advance a social or public policy initiative.”

The final message from this report is that efforts to improve the use and usefulness of systematic reviews must be evaluated, and these findings must themselves be disseminated and implemented.