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2015 Dietary Guidelines Advisory Committee (DGAC) Nutrition Evidence Library (NEL) Methodology

Develop Systematic Review Questions and Analytic Frameworks

The DGAC identified, refined, and prioritized the most relevant topics and then developed clearly focused systematic review (SR) questions that were appropriate in scope, objective, and targeted important policy relevant to public health issue(s). SR questions must be specific enough to be researchable using NEL methodology, but broad enough to not overly limit the scope of the literature search. Once topics and SR questions were generated, the DGAC developed an analytical framework for each topic in accordance with NEL methodology. These frameworks clearly identified the core elements of the SR question/s, key definitions, and potential confounders to inform development of the SR protocol.

The core elements of an SR question include Population, Intervention or Exposure, Comparator, and Outcomes (PICO). These elements represent key aspects of the topic that are considered in developing a SR framework. An analytic framework is a type of evidence model that defines and links the PICO elements and key confounders. The analytical framework serves as a visual representation of the overall scope of the project, provides definitions for key SR terms, helps to ensure that all contributing elements in the causal chain will be examined and evaluated, and aids in determining inclusion and exclusion criteria and the literature search strategy.

Example of an NEL systematic review analytical framework:

Example of an Analytical Framework: Dietary Patterns and Cancer

Related 2015 DGAC Methodology topics:

Last Updated: 12/16/2014