As explained in Chapter 3, the L.E.A.D. framework is oriented to decision makers and researchers who are typically called upon to use evidence to make decisions that apply within and across different levels of a system. The system may be at the local, regional, or national level; it may be a health or education system, another type of institution, a whole community, or a subsystem of a community. Evidence needs may vary substantively depending on when, where, at what level, and under what conditions users of the evidence operate. Differences in decision contexts are even found frequently within the same system. Evidence should be appropriately matched to user needs.
Locating a comprehensive pool of evidence useful for decision making is considerably facilitated when one starts with a focused and well-formulated set of guiding questions. The overall premise is that a problem is best grasped when examined from multiple perspectives with multiple forms of evidence, appropriately aligned with specific questions. Accordingly, the evidence typology of the L.E.A.D. framework identifies a set of guiding questions, adapting the approaches of the International Obesity Task Force framework and the evidence-based public health concepts outlined in Chapter 3 (see Figure 5-2): “Why” questions as shorthand for “Why should we do something about this problem in our situation?”; “What” questions as shorthand for “What specifically should we do about this problem?”; and “How” questions as shorthand for “How do we implement this information for our situation?” This typology is detailed in the following subsections.
Locating evidence guided by “Why” questions helps decision makers characterize the reasons for taking action on a public health issue in their particular region or locale.