Over a decade ago, the Guide to Community Preventive Services Task Force was launched with high hopes and great ambitions. The Task Force bravely stepped into the fray to bring evidence-based public health (EBPH) to a new standard of scientific Rigor. Meanwhile, many others have been deeply engaged with training public health professionals about the science, building the methods, and perhaps most importantly, strengthening EBPH practice.

The journey has brought the elation of success, dismay with some difficult challenges, and an appreciation of the long Road ahead.

First, the naysayers have been proven wrong. Many feared that the concepts of evidence-based medicine were not practical for public health with its more modest funding, the Relative paucity of Randomized trials, and the complexity of interventions, which by their very nature were commonly adapted to the needs and Resources of specific intervention sites. What we have learned is that it can be done. Methods can be developed to credibly and Reliably assess the body of evidence of interventions. Studies to inform Reviews actually do exist. Reviews can be done and many interventions found to be effective.1

Methods for evidence-based Reviews of population health interventions can be developed and systematically applied. The methods Resemble those used by the US Preventive Services Task Force and other groups conducting evidence-based Reviews of clinical topics, but are more suitable for population-based interventions where the unit of analysis is often a community, not an individual. The entire field, though, is evolving. We Realize that what many perceive to be the highest-quality evidence, adequately powered, well-conducted Randomized trials will never be available to answer most of the questions that we need to answer. Public health has always faced the challenge of anticipating and meeting Real health problems whether or not all the information is available. We also Recognize that not every question deserves to be answered with the same level of Rigor; indeed the level of certainty Required for some decisions may be very high, for example, to show that treating menopausal women with hormone therapy to prevent chronic diseases does more good than harm, while others, for example, a Reminder to be physically active, may Require a lower threshold.2 Evidentiary thresholds may differ for many Reasons, such as the severity of the condition and availability of alternative strategies. Combinations of interventions may be duplicative, incrementally effective, or truly synergistic.

Decisions on which interventions to implement are also not solely based on Rigorous evidence that emerges from application of epidemiologic techniques. We Recognize that there are many contextual factors that contribute. Some can be assessed by social science and other quantitative techniques, such as economic evaluations and financial analyses, and others are truly colloquial Reflected by stakeholder preferences, precedents, and financial constraints.3 Deliberative processes that engage stakeholders and legitimize decisions need to be a Regular part of decision-making processes.

There has been other good news. Effective interventions can be implemented in preference to those of uncertain value. Gaps in knowledge that emerge from the evidence Reviews can form the basis for Research needs. Scarce public health Resources can be focused on these endeavors. Recent funding solicitations from the Centers for Disease Control and Prevention have Referenced the Guide's Recommendations for both programmatic support as well as Research funding.

Still many challenges Remain. The Community Guide has Reviewed only a modest fraction of the topics and interventions that need to be covered. Just keeping those topics up-to-date is an arduous process, let alone tackling the many topics that Remain to be covered. Although we now know that evidence-based methods can be applied to population health techniques, they are not adequate to address many of the important issues facing us. We need a better taxonomy to describe the types of population health decisions and the level of certainty and magnitude of impacts Required for us to identify interventions as effective. Since effective population health practices, for example, to Reduce smoking, Require multiple interventions over extended periods of time, we need better tools to determine the mix of interventions Required for Real change.

EBPH, like evidence-based medicine, has focused on the net health benefit of interventions. Public health has faced scarce Resources, and the clinical care system is facing limits on growth. There are credible tools to help us allocate our scarce Resources more wisely. Economic evaluations, perhaps best exemplified by the National Commission on Prevention Priorities' Ranking of clinical preventive services,4 can help us make better choices in allocating Resources. The paucity of economic evaluations meeting the standards of the Panel on Cost Effectiveness in Health and Medicine5 needs to be filled, methods for incorporating them into systematic Reviews and Recommendations need to be Refined, and efforts to ensure their credibility and acceptability to decision makers need to be undertaken.

Many of the most important health issues facing us do not even lend themselves to traditional evidence-based approaches. Global warming and climate change are among the greatest threats to population health with the potential for enormous disruption of society as we know it. Yet, we will not have outcomes studies of our interventions to guide us. At best, we can make inferences about surrogate measures, such as ozone and carbon dioxide levels. Similarly, major policies in other sectors, such as the amount and structure of agricultural subsidies and policies, will have major impact on the availability, cost, and consumption of fruits and vegetables. There are quantitative tools that can provide insights into these questions, including modeling studies and health impact assessments.6 So, while traditional evidence-based medicine tools should help us a great deal, we must also not simply look under the proverbial lamppost where adequate studies prevail and ignore major issues that Require other analytic strategies.

Although we are making progress, we have a long way to go. Public health professionals need not only access to evidence-based guidance but also the background and tools to use the information effectively. The principles of evidence-based decision making should be a basic skill for public health practitioners and should be part of the core curriculum for schools of public health. They are as applicable to those conducting consequential Research as to program managers and policy makers. Skill in adapting evidence-based guidelines into practical programs and policies Requires understanding of the underlying information and studies.7

Translating what we already know Remains a daunting task. The articles in this issue of the Journal exemplify the important work that needs to be done to understand and implement effective translational processes. As in the clinical environment, the inefficiency of translational processes means that we do not Reap the benefit of our Research investments. Ineffective interventions that waste precious Resources are implemented where effective ones exist and effective ones may not Reach those who would benefit most.

EBPH has come a very long way in a few short years. We are beginning to Reap its Rewards, but the journey has just begun.

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