and beverage environments; message environments; health care and workplace environments; and school environments.
In 2009, the Measures Project, led by CDC, released recommendations for 24 community-based strategies for obesity prevention along with an associated indicator, data collection questions, and potential data sources to track progress on each strategy (Kettel Khan et al., 2009). Strategies were grouped into six categories: food and beverage availability; healthful food and beverage options; breastfeeding support; physical activity promotion and limiting sedentary activity among children and youth; community safety to support physical activity; and community coalitions for creating change in the key environments. Also, CDC’s Guide to Community Preventive Services provides timely updates to evidence-based recommendations for action on an array of public health issues, including nutrition, physical activity, and obesity prevention (Task Force on Community Preventive Services, 2005, 2011; Truman et al., 2000).
The National Prevention Council, under the direction of the Surgeon General, published the National Prevention Strategy (NPC, 2011); priority strategies include healthful eating and active living. For each priority, the Strategy recommends target actions, key indicators, and 10-year goals. Grounded in a science base, the Dietary Guidelines for Americans (HHS, 2010a) and Physical Activity Guidelines for Americans (HHS, 2008) offer similar guidance. Other scientific and professional associations, such as the American Heart Association and the Academy of Nutrition and Dietetics, also provide recommendations for obesity prevention.
Context for Evaluation Activities
Another consideration for evaluation activities is the context in which the interventions to be evaluated will occur. Context closely links with the concept of assessment (baseline data characterizing the problem) and surveillance (ongoing or periodic data collection, analysis, and interpretation). At the national or state levels, assessment might include surveillance to assess changes in obesity rates and monitoring of policy changes, and summative evaluation assessing the association of the two. At the community level, assessment might take the form of a system to monitor changes in interventions and the built environment over time.
The context for evaluation activities includes the how much of what, how, by whom, and by when stated in the objectives for each intervention or strategy. The “how much” is stated as a target percentage, mean, or rate. “What” may be singular or complex, often referring to multiple-component, multi-sector, and multi-level interventions to assure conditions for healthful eating and physical activity (IOM, 2012a). Comprehensive interventions provide challenges for “what” and “how” to evaluate. For a single intervention strategy (e.g., improve the quality of foods and beverages consumed), numerous indicators exist (e.g., consumption of sugar-sweetened beverages, fruits, vegetables, whole grains, lower-fat dairy, etc.). Furthermore, for a single indicator (e.g., consumption of sugar-sweetened beverages or fried foods), many potential measurement methods exist, including review of archival records (e.g., of sales), observations (e.g., food disappearance, plate waste), and behavioral surveys (e.g., food frequency questionnaire, 24-hour recall). Each indicator and its associated measurement vary in quality (accuracy, sensitivity, specificity), utility, and resource requirements. These factors must be considered when offering guidance for how to evaluate. The “by when” aspect of the health objective informs the timing of the evaluation activities, for example, whether annually or at some other time interval, and the anticipated prospect of observing progress after a given interval of time.