“What” questions, used to identify the effectiveness of interventions, guide the gathering of information on whether a specific intervention or interventions had the intended effects and contributed to addressing the problem in the expected manner or with the expected impact. In the Arkansas case, the subsequently established program of annual monitoring provides data that can be used to determine whether the various components of the initiative are resulting in improvements in the relevant school environment or child and parent behaviors. Likewise, definitive evidence for the effects on obesity prevention of such initiatives as posting calorie content on chain restaurant menus will not be available until the interventions have been in effect for a period of time. In the interim, effects on consumer behavior can be modeled for defined populations based on such data as the numbers of such restaurants, sales data on menu items with different calorie content, the types of consumers who patronize these restaurants, and how chain restaurant purchases influence their caloric intake.

“How” questions, used to identify issues related to relevance and implementation, can guide the gathering of information on what actually took place when an intervention was undertaken. Answers to these questions can be used to inform decisions about what changes might be needed going forward, to explain why the intervention might not have worked as well as intended, or to understand why costs were higher or lower than those initially estimated. The Arkansas monitoring program, for example, collects data on the quality and process of implementation (Thompson and Card-Higginson, 2009). Likewise, the methodology used in the Assessing Cost-Effectiveness in Obesity Study (ACE-Obesity) can help guide future decisions on interventions to prevent obesity in children and adolescents (Carter et al., 2009; Haby et al., 2006). In this study, researchers assessed absolute costs and potential cost savings to help determine the cost-effectiveness of 13 different interventions applied populationwide.

Applying the Evidence Typology: An Illustrative Example

In New York City, a decision was made to implement a policy requiring restaurants to publish calorie information on menus (Mello, 2009). “Why,” “What,” and “How” questions that guided, or may have guided, the search for and synthesis of evidence to support this broad-based policy decision are listed in Box 5-2. While the case report from which the questions were derived does not detail the exact decision-making processes, the relevant types of evidence that may have been used can be inferred from the documentation provided.

To approach this issue by applying the L.E.A.D. framework, decision makers would obtain a full picture of the scope and dimensions of the obesity problem in the city. For example, questions 1 to 5 in Box 5-2 could help decision makers assess the city’s health needs comprehensively. Much of this evidence speaks to various aspects of the obesity prevalence issue, correlates of obesity, and relevant lifestyle factors in a situation-specific manner. This evidence might be collected by using archival data from

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