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Nutrition Evidence Library Systematic Review Methodology


Nutrition Evidence Library (NEL) systematic reviews (SRs) are designed to address food and nutrition-related topics that are important to Federal government policy and program decision-making. The methodology used by NEL to conduct SRs is designed to be transparent and reproducible, and to minimize bias. The following represent overarching principles for the NEL process:
  • The Technical Expert Collaborative (TEC) makes all substantive decisions required during the process.
  • NEL staff provides facilitation and support to ensure that the process is consistently implemented in accordance with NEL methodology.
  • NEL uses document templates, which serve as a starting point and are tailored to the specific review.
The NEL works with a group of scientific experts, from academia and the Federal government, to conduct systematic reviews, and uses state-of-the-art methods to review, evaluate, and synthesize food and nutrition research. The NEL process has six steps:
  • Step 1: Develop systematic review questions
  • Step 2: Search, screen, and select studies to review
  • Step 3: Extract data and assess the risk of bias of the research
  • Step 4: Describe and synthesize the evidence
  • Step 5: Develop conclusion statements and grade the evidence
  • Step 6: Identify research recommendations

Organization of the Systematic Review Team

The roles and responsibilities of those individuals involved in NEL SR projects are described below.
Systematic Review Management Team
Each NEL SR project is planned, organized, and guided by a Systematic Review Management Team composed of Federal nutritionists and two librarians who have been trained in systematic review methodology.
  • NEL Lead: Responsible for all aspects of planning, facilitating, and conducting the work necessary for timely execution of SRs.
  • NEL Secondary Lead: Provides support to the NEL Lead as needed. May play the lead role in planning, facilitating, and conducting some SRs.
  • NEL Librarian: Works with the NEL Lead and Secondary Lead to develop implement, refine and document the literature search strategies.
  • Technical Advisor: NEL staff member with recognized subject matter expertise in an area who may be appointed to assist the NEL Lead in the SR development process and technical execution.
Technical Expert Collaborative
A Technical Expert Collaborative (TEC) is a group of six to eight leading scientists who are convened to participate in a SR project on a specific topic. The TEC is composed of domain experts, nutrition scientists, clinicians, epidemiologists, methodologists, communicators, and/or end users of a review. TEC members aid the Systematic Review Management Team by reviewing and providing expert feedback to refine SR materials and synthesize the body of evidence to answer important diet-related questions. A TEC is not a Federal Advisory Committee (FAC), and therefore, does not provide formal group advice or recommendations to the government, but instead provides individual input on NEL-related materials.
NEL Fellows and Abstractors
NEL Fellows and Abstractors are National Service Volunteers from across the United States with advanced degrees in nutrition or a related field. They are trained to review individual research articles included in NEL SRs. They extract data from the research articles and post this information to data fields in evidence worksheet templates in the NEL online portal, and assess the risk of bias of each individual study using the NEL Bias Assessment Tool. NEL Fellows, who contribute a higher level of commitment to the NEL, may also provide support to the NEL by screening literature and assisting in preparation and/or review of other components of a NEL SR.

More information on the Nutrition Evidence Library Systematic Review Methodology

Last Updated: 05/05/2014