EAL Systematic Review Process

Systematic Reviews vs Narrative Reviews

A systematic review is a high-level process that collects and critically analyzes multiple research studies or papers on a clearly formulated question using explicit methods to identify, select and critically appraise the primary research. Systematic reviews differ from narrative reviews in that narrative reviews tend to be mainly description and do not involve a systematic search of literature and are often based on author selection.  The EAL is composed of only systematic reviews.

Scoping Reviews 

In order to explore the literature describing nutrition care and to determine the need for a systematic review and evidence-based practice guideline, the EAL conducts an evidence scoping review. In an evidence scoping review, availability of literature on a broad topic is identified and categorized to describe the nature and extent of the literature in the topic area 1-3. This information may be used to define the scope and inform PICO-formatted research questions for a systematic review. The end product of an evidence scoping review includes presentation and description of the literature available on a particular topic, but does not include data synthesis or quality assessment of studies and typically doesn’t include results of the primary studies 1. Results of the evidence scoping review can direct a systematic review expert workgroup regarding where, within a broad topic area, systematic reviews are lacking (primary research exists, but current systematic reviews do not exist) and where there is sufficient synthesized evidence and duplicate efforts should be avoided. Evidence scoping reviews can also inform researchers of where there are research gaps in primary literature that need to be addressed in order to advance, in this case, nutrition practice.

1. Arksey H, O'Malley, Lisa, Taylor & Francis (Routledge), 2009-08-17T10:59:18.476. Scoping studies: towards a methodological framework. 2009.
2. Levac D, Colquhoun H, O'Brien KK. Scoping studies: advancing the methodology. Implementation science : IS. 2010;5:69.
3. The Joanna Briggs Institute. Joanna Briggs Institute Reviewers’ Manual: 2015 edition / Supplement2015, Australia.

EAL® Methodology and Process

The methodology followed by the Academy is a rigorous 5-step process for evaluating food and nutrition questions. This work is conducted by a team of experts in the topic area and analysts trained in research analysis. Meticulous methods and specially designed templates are used throughout the process to ensure objectivity, transparency and reproducibility of the process.

Steps in the Evidence Analysis Process

  • Step 1: Formulate the Evidence Analysis Question - Specify a focused question in a defined area of practice. Three key items are used to generate good quality questions: an analytical framework to identify links between factors and outcomes; the PICO format to write questions; and the Nutrition Care Process to serve as a framework.
  • Step 2: Gather and Classify the Evidence - This step involves developing a search plan to conduct a detailed literature search. The search plan clearly defines the inclusion and exclusion criteria and identifies the key search terms and outcomes necessary to conduct a comprehensive search. The search plan and all literature searches results are documented and assessed for inclusion eligibility. Excluded articles are listed along with reasons for exclusion.
  • Step 3: Critically Appraise Each Article (Risk of Bias) - This step involves critically assessing each included article for methodological quality. Each study is evaluated based on appropriateness of study design and the quality of how the study was conducted by using the Academy's risk of bias tool called the Quality Criteria Checklist (pdf). 
  • Step 4: Summarize the Evidence - This step involves achieving two major tasks. First, key data from the included articles is extracted by using the Academy's web-based data extraction template. Second, summarizing the evidence extracted from each study into a brief, coherent, and easy-to-read summary. The end result of this phase is called the Evidence Summary.
  • Step 5: Write and Grade the Conclusion Statement - This step includes developing a concise conclusion statement for the research question and assigning a grade to the conclusion statement. The grade reflects the overall strength and weakness of evidence in forming the conclusion statement. The grading scale used by the Academy is: Grade I (good/strong), II (fair), III (limited/weak), IV (expert opinion only), or V (not assignable) (pdf)

To learn more about the Academy's rigorous process:

EAL Project Team

The development of an EAL systematic review is team-based and includes:

  • Council on Research: Provides oversight to the EAL; approves topics; appoints workgroups
  • Methodologist: Ensures sound systematic review methods and rules are followed
  • Project Manager: Manages project; facilitates work of the team; works with the workgroup chair to prepare agendas and facilities consensus
  • Lead Analyst: Creates sort lists; manages work of the evidence analysts; drafts evidence summaries; creates tables
  • Medical Librarian: Conducts and conducts literature searches
  • Workgroup and Workgroup Chair: Group of 6-8 exerts on topic who formulate the research questions; set inclusion/exclusion criteria; review material; approve evidence summaries and conclusion statements; grade strength of evidence; approve and rate recommendations
  • Patient Advocate*: Provide viewpoint and input from patient, caregiver or public perspectives
  • Evidence Analysts: Experts in critically appraising research articles and abstracting relevant data 
  • Guideline Reviewers: Individuals with working knowledge of the guideline topic who conduct external review and complete an evaluation of evidence-based nutrition practice guideline.
  • Academy Staff: Development and maintenance of EAL; conducts training of project team; business aspect of the EAL

A listing of the project team is available from each project's landing page. Expand the section titled Project Team to view the individuals, conflict of interest disclosures and financial support for every EAL systematic review and guideline. To learn how to get involved in an EAL project, visit Join the EAL Team.

Selection of Articles 

Articles included for analysis on the EAL are:

  • English Language Publication
  • Human Subject Research
  • Peer-Reviewed Publication1
  • Meet the specific inclusion criteria (within range of years of publication, ages of subjects, size of sample, etc.) established for the specific research question. The inclusion and exclusion criteria are found in the Search Plan and Results linked to each question.

1Peer-Reviewed: articles accepted for evidence analysis must be peer-reviewed and published in a juried publication.

The Academy does not use the so-called "grey" literature. Examples of grey literature include technical reports from government agencies or scientific research groups, working papers from research groups or committees, white papers, position papers, abstracts, conference reports, newsletters, and government reports.

To date, the EAL systematic reviews and guidelines address topics related to human nutrition; therefore, only research identified as applicable to humans has been included.

The research articles are not available on the EAL.  A link to PubMed is provided for each included article. Users can access the article via PubMed, their institution's library, or visit each journal website for free access or to purchase a one-time use. Academy members have free access to articles from the Journal of the Academy of Nutrition and Dietetics,

Managing Conflicts of Interest

A conflict of interest is traditionally defined as a personal or financial interest or a duty to another party which may prevent a person from acting in the best interest of the intended beneficiary.

It is not the mere existence of an actual or potential conflict of interest that renders conduct unethical; rather, it is the way in which the conflict is handled or addressed. The Academy requires each workgroup member to continually be cognizant of fiduciary duties to the Academy arising out of their positions of confidence within the organization. Workgroup members are required to complete the EAL’s online disclosure form (pdf) and to verbally disclose any potential conflicts at the start of each teleconference. Disclosure.

Funding of the EAL 

The Academy of Nutrition and Dietetics is the primary source of funding for the Evidence Analysis Library® (EAL®).  External funding for the EAL has enabled the Academy to publish much more content than would have been possible through Academy funding only. External funding includes government agencies, nonprofit foundations, collaborations with professional associations, Academy groups (Foundation, DPGs) and industry. 

All externally funded projects are funded as unrestricted grants, meaning the funding entity has no input on the project including the workgroup selection, question formulation and outcome.  In addition, all externally funded project topics must meet the EAL’s mission. Funding information is published on the EAL under the “Project Team and Disclosures” section of each systematic review.

The following EAL funding opportunities are not open to industry funding:

  • Evidence-based nutrition practice guidelines/recommendations
  • Evidence-based nutrition practice resources
  • Academy position papers

Regardless of the funding sources, the Academy maintains full control over the content and process of ALL projects. Only the expert workgroup members can formulate the evidence analysis questions, set the inclusion/exclusion criteria; review the articles and evaluate the research; grade the conclusion statements and provide the final grade. All workgroup members are carefully vetted and must disclose any potential conflict of interest.

Recognized Methodology

The methodology followed by the Academy is highly recognized.  We are convinced that our process is simply the best.  Consider the following:

  • The Academy's Evidence Analysis process was recognized by JCAHO as exemplary of bringing the best research to practice.
  • The Academy's Evidence Analysis process was adapted by the FDA to assess the type of qualified health claim that can be put on food labels.
  • The Academy's research staff has trained staff and task force members for USDA, DHHS, CDC and FDA.

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