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Teachers College, Columbia University
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Changing the Paradigm in Obesity Studies

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BEYOND RANDOMIZED TRIALS

TC's Madhabi Chatterji says, "The parallels between public health and education are numerous. In both, we face the need to study complex social interventions in their natural environments.”

About 68 percent of American adults are overweight or obese. Among children, the rate is nearly 32 percent. Obesity presents a major challenge for healthcare providers, policymakers and other decision-makers who need relevant and useful evidence of promising obesity prevention actions. In 2008, a committee of experts including Madhabi Chatterji, Associate Professor of Measurement, Evaluation and Education, was convened by the Institute of Medicine (IOM) of the National Academy of Sciences. The committee examined innovative ways by which the existing evidence base and research on obesity and obesity prevention programs could be accessed, evaluated and made useful to policymakers. The committee developed a practical, action-oriented framework to guide policymakers for using the available base of research and other forms of evidence relevant to obesity-prevention policies and programs. The framework included suggestions for the research community to produce further high-quality research evidence that is informative for public health policymakers at all levels. The framework, contained in a report entitled “Bridging the Evidence Gap in Obesity Prevention: A Framework to Inform Decision Making,” was released on April 23.
In an interview, Chatterji said she “was honored” to be chosen as a member of the highly selective committee—which included well known obesity prevention scholars, doctors, medical researchers, state legislators, economists and public policy experts—because of her specializations in research study designs. Chatterji was one of two methodologists on the committee. The committee released its report only after its 16 members came to consensus.
 
“Federal policies on evidence-based practices in public health and education sectors borrow from ideas in evidence-based medicine, which was the first to promulgate the notion that randomized experiments are the very best means for gathering evidence on effective therapies,” Chatterji said. “This long-standing tradition has influenced how research has been conducted and how researchers and evaluators are trained in the health fields, education and the social sciences at large. It has also influenced the current evidence pool that is available to policymakers and practitioners responsible for making important decisions about programs and policies every day. When programs and policies involve complex systems of variables, including personal, social and environmental factors such as individual values and community culture, their effects on large populations simply cannot be properly captured with randomized controlled trials alone."
 
Instead, the IOM’s framework suggests an interdisciplinary approach for choosing from a range of research methods and study designs. “Using the framework,” the committee states in its report summary, “involves innovative approaches to generating, identifying, evaluating and compiling evidence—taking the broad, transdisciplinary perspective.
 
“Overall,” the committee’s summary states, “the framework encourages decision makers and researchers to look at obesity from a systems perspective, as a complex, population-based health problem that has many contributing factors.” Chatterji adds that the committee’s recommendations are for building and using a broad evidence base, using formal, research-based evidence as well as other credible forms of evidence, for example, expert opinion released by respected national agencies or groups.
 
The IOM committee recommended that all stakeholders in obesity research—government and private funders, research institutions and educators, journal editors, and professional organizations—need to incorporate systems thinking into the research process and the ways in which research is used when addressing population-based health problems.
 
They also need to apply what the committee calls the L.E.A.D. framework for decision making. After specifying the questions that they wish to answer (for example, Do healthier food options in school cafeterias result in lower obesity rates?), decision makers applying the framework would need to: Locate evidence, Evaluate the evidence for quality and relevance, Assemble the evidence taking into consideration the proposed uses, and then use the evidence to inform Decisions.
 
Other recommendations made by the committee include:
 
•     Building a system of resources (such as people, compendiums of knowledge, registries of implementation experience) to support evidence-based public policy, decision making, and research for addressing complex health challenges, such as obesity prevention;
 
•     Establishing broader but rigorous standards for evidence quality;
 
•     Supporting the generation of evidence, taking into account the degree to which the findings can be generalized, and related implementation issues at every stage, from conception through publication.
 
•     Encouraging collaboration among researchers in a variety of disciplines so as to utilize a full range of research designs; and
 
•     Communicating, disseminating, evaluating and refining the L.E.A.D. framework.
 
TC Deputy Provost John Allegrante, who has been studying changes in the prevalence of overweight and obese children and adolescents in Iceland and other countries, was invited by the IOM to review the report’s findings. “The report provides a review of several substantial scientific literatures containing a broad spectrum of data-based evidence about the causes of obesity,” Allegrante says. “It also discusses the evidence available to support decision-making in selecting population-based prevention efforts in the control and prevention of obesity, and it suggests the kinds of additional evidence that need to be generated by future research in the prevention of obesity.” Allegrante adds: “But if we are to foster the kind of new research the report encourages—research designed to utilize and value a wider range of the sources of evidence beyond that generated by randomized controlled trials—then there will need to be major policy changes in the peer review process, the composition of peer review panels, and the criteria that are utilized at the National Institutes of Health and the Centers for Disease Control and Prevention, and other funding agencies, when making funding decisions in support of such research.”
 
Chatterji says she hoped that the framework would change the way evidence is used and generated in the obesity area, as well as influence how evidence is viewed in other fields like education that also aim to affect populations on a large scale. “The parallels between public health and education are numerous,” she said. “In both, we face the need to study complex social interventions in their natural environments and must think outside the box in our search for suitable research designs and tools.”
 
More information, including a summary and full text of the IOM report, may be obtained at: http://www.iom.edu/Reports/2010/Bridging-the-Evidence-Gap-in-Obesity-Prevention-A-Framework-to-Inform-Decision-Making.aspx
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