nomic burden of obesity with that associated with other health problems (Chenoweth and Associates, 2009; Finkelstein et al., 2009; Wolf and Colditz, 1998). Finkelstein and colleagues (2009), for instance, use data from the 1998 and 2006 Medical Expenditure Surveys to estimate health care costs attributable to obesity for all health care payers. When programs are competing for funding, such an evidence pool is necessary to support decisions.

“What” Questions

Locating evidence to answer “What” questions helps decision makers assess the effects of interventions with the potential to yield the best health outcomes and to ascertain the optimal conditions for obtaining those outcomes. Table 5-2 lists some examples of areas of concern addressed by “What” questions and the corresponding evidence that might be gathered.

To answer “What” questions, decision makers require evidence on the effects or impact of particular interventions on specific health outcomes over the short or long

TABLE 5-2 Areas of Concerns and Examples of Evidence Needed: “What” Questions

Area of Concern

Examples of Evidence Needed

Presumed mechanisms of intervention effects in target populations


• Intervention theory or logic

Underlying assumptions (explicit or implicit) about how the intervention will improve health outcomes

• Causal pathways

Expected direct or indirect pathways linking the intervention to the outcomes at one or more levels and for different demographic groups

• Multiple causal levels for multiple influences

Intervening or interacting influences that might facilitate or hinder the effects in groups at risk

Effectiveness of intervention based on empirical studies or simulations


• Links between intervention delivery and outcomes

Evidence that the intervention leads to the outcomes, including evidence of authentic and consistent implementation when effects were obtained

• Comparative outcomes

Effects of an intervention on the outcome in comparison with other intervention options or no intervention, including evidence on effects in different demographic groups

• Sustained effects

Evidence that effects of the appropriately implemented intervention are sustained over time

• Contextualized effects

Evidence of circumstances under which the evidence for effectiveness of the intervention is strongest, including evidence of other factors that influenced or interacted with the intervention (e.g., individual, family, community, or school factors)

• Unintended (unexpected) consequences

Positive or negative outcomes that lie outside the theory or underlying logic of the intervention

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