Methodological Approach to the Task
The Committee on Evaluating the Process to Develop the Dietary Guidelines for Americans, 2020–2025 (2020–2025 DGA) addressed each of the three sub-tasks within its Statement of Task (Chapter 1, Box 1-2) separately. The committee’s midcourse report, Evaluating the Process to Develop the Dietary Guidelines for Americans, 2020–2025: A Midcourse Report, (NASEM, 2022a) describes its approaches to Tasks 1 and 2. This chapter explains the committee’s interpretation of Task 3 (Box 3-1) and the approach it used to gather and assess relevant evidence to inform and support its findings and conclusions related to Task 3. In both the midcourse report and this report, the committee honored the Department’s request to restrict the period of analysis to the date of the release of the 2020–2025 DGA, which occurred in December 2020 (NASEM, 2022b).
THE COMMITTEE’S INTERPRETATION OF TASK 3
The committee’s overall task was initially described in Congress’s 2021 Consolidated Appropriations Act (see Chapter 1), which is the source of the language for Task 3 (Box 3-1). The U.S. Department of Agriculture (USDA) and the National Academies of Sciences, Engineering, and Medicine (the National Academies) developed specific study questions associated with each of the three sub-tasks of the overall task (e.g., Box 3-1, “Question for Task 3”).
The committee interpreted Task 3 as a request to analyze how the 2020–2025 DGA would have differed in terms of timeline, cost, and integrity if they had been developed as part of a process that fully implemented the seven recommendations from the 2017 National Academies report (NASEM, 2017). Some recommendations were not implemented as recommended (even though the Departments (USDA and the Department of Health and Human Services [HHS]) might have taken steps to address them in other ways) and some were essentially fully implemented. For the remaining recommendations, the committee distinguished between those that were partially or substantially implemented to indicate those that needed more or less additional work, respectively, to achieve full implementation. When the committee lacked direct information with which to perform its analysis, the committee drew upon its scientific expertise and judgment when a recommendation had not been implemented. In other words, full implementation of the recommendation served a counterfactual or “what if” to the actual process used to develop the 2020–2025 DGA (Levy, 2015). The committee’s expert judgment was required because implementation could have taken different forms (e.g., related to the size and composition of the Dietary Guidelines Planning and Continuity Group [DGPCG], the specific experts included in the Technical Expert Panels [TEPs], or the systems science approaches adopted). The committee’s expert judgment was especially required for recommendations for which the gap was large between the recommendation and the actual process used to develop the 2020 Dietary Guidelines Advisory Committee Scientific Report (2020 DGAC Scientific Report) (DGAC, 2020). In cases of partial or substantial implementation, the form that implementation took provided evidence the committee could draw on to form conclusions about how the 2020–2025 DGA would have differed with full implementation.
The extent to which the recommendations in the 2017 National Academies report were implemented was first evaluated as part of Task 1 (see Chapter 1, Box 1-2) and included in the committee’s midcourse report (NASEM, 2022a). To address Task 3, the committee considered actions taken by the federal agencies to develop the 2020–2025 DGA and compared those actions to the actions recommended in the 2017 National Academies report. It is noteworthy that Tasks 1 and 3 have different outcomes. In Task 1, the outcome was the extent of implementation of the 2017 National Academies report recommendations. In contrast, in Task 3, the outcome was the potential implications of full implementation of the 2017 National Academies report recommendations on the 2020–2025 DGA. For Task 3, the committee considered actions identified in Task 1 as well as additional relevant actions taken by the agencies to develop the DGA.
The committee developed a diagram (Figure 3-1) to illustrate its approach to Task 3. The diagram begins with the values that the 2017 report committee used to develop its recommendations (NASEM, 2017). These values were designed to improve the rigor and integrity of the process to create the DGA and improve the trustworthiness of the guidelines. The committee viewed rigor and integrity in the DGA process as prerequisites for establishing an optimal level of trustworthiness in the resulting guidelines. The committee identified two key constraints to full implementation of the 2017 National Academies report’s recommendations during the 2020–2025 DGA process. One constraint was the timing of the publication of the 2017 National Academies report relative to the timeline for developing the 2020–2025 DGA (i.e., the 2017 report was published more than a year after the 2020–2025 DGA process had begun). A second constraint was the monetary cost of implementing the recommendations, which could reflect additional time spent by current staff, addition of new staff with specific skills, or acquisition of new technologies.
METHODOLOGICAL APPROACH TO TASK 3
The committee responded to Task 3 using information obtained in the process of responding to Tasks 1 and 2, specifically, information that helped it ascertain actions taken by the Departments to develop the 2020–2025 DGA. As the committee noted in its midcourse report (NASEM, 2022a), this included verbal information gathered during virtual open sessions that provided an opportunity for the committee to engage in dialogue with representatives of the sponsors of this report as well as key members of the committees that created the 2017 National Academies report and the 2020 DGAC Scientific Report (Appendix D; NASEM 2022c, d). The committee also gathered written information (Appendix D) that the Departments provided
in response to the committee’s specific questions during open sessions (NASEM, 2022c), reviewed federal reports (i.e., previous editions of the DGA and DGAC Scientific Reports), and websites (e.g., DietaryGuidelines. gov and NESR.USDA.gov). When necessary, the committee consulted the scientific literature for additional information about the background of an issue or to go beyond the information available in federal reports and websites. The committee also evaluated possibly relevant new information as it became available (e.g. Achterberg et al., 2022).
To provide an additional way to assess the implementation of the seven recommendations, the committee considered the five values that were the basis for the 2017 National Academies report and described the ways in which it concluded that these values had or had not been addressed during the process to develop the 2020–2025 DGA. The committee considered the recommendations individually as well as in related groups when developing its conclusions. The Statement of Task for this committee excludes providing recommendations, which the committee interpreted to include any expert opinion or advice regarding future implementation.
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DGAC (Dietary Guidelines Advisory Committee). 2020. Scientific report of the 2020 Dietary Guidelines Advisory Committee: Advisory report to the Secretary of Agriculture and the Secretary of Health and Human Services. Washington, DC: U.S. Department of Agriculture, Agricultural Research Service.
Levy J. S. 2015. Counterfactuals, causal inference, and historical analysis. Security Studies 24(3):378-402.
NASEM (National Academies of Sciences, Engineering, and Medicine). 2017. Redesigning the process for establishing the Dietary Guidelines for Americans. Washington, DC: The National Academies Press. https://doi.org/10.17226/24883 (accessed September 22, 2022).
NASEM. 2022a. Evaluating the process to develop the Dietary Guidelines for Americans, 2020–2025: A midcourse report. Washington, DC: The National Academies Press. https://doi.org/10.17226/26406 (accessed September 22, 2022).
NASEM. 2022b. Evaluating the process to develop the Dietary Guidelines for Americans, 2020–2025. Committee meeting 1 open session. https://www.nationalacademies.org/event/08-12-2021/evaluating-the-process-to-develop-the-dietary-guidelines-foramericans-2020-2025-committee-meeting-1 (accessed September 22, 2022).
NASEM. 2022c. Evaluating the process to develop the Dietary Guidelines for Americans, 2020–2025. Committee meeting 34 open session. https://www.nationalacademies.org/event/06-23-2022/evaluating-the-process-to-develop-the-dietary-guidelines-foramericans-2020-2025-committee-meeting-34-open-session (accessed September 22, 2022).
NASEM. 2022d. Evaluating the process to develop the Dietary Guidelines for Americans, 2020–2025. Committee meeting 32 open session. https://www.nationalacademies.org/event/06-06-2022/evaluating-the-process-to-develop-the-dietary-guidelines-foramericans-2020-2025-committee-meeting-32-open-session (accessed September 22, 2022).
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