6

A Research Agenda for Improving Interventions to Reduce Food Waste and Their Implementation

Much remains to be learned about how food waste at the consumer level can be reduced. Researchers from a number of disciplines are studying many aspects of this challenge, and they have already provided the foundation for meeting this urgent challenge, as described in this report. To sustain the strategy laid out in Chapter 5, however, ongoing work is needed to address significant gaps in the knowledge base. This concluding chapter summarizes the gaps identified throughout the report, and offers the committee’s suggestions for research priorities. The research gaps relate to two distinct but interconnected areas:

• understanding drivers of consumer behavior and designing interventions to change that behavior, and
• understanding how promising interventions can be implemented effectively.

UNDERSTANDING DRIVERS OF CONSUMER BEHAVIOR AND DESIGNING INTERVENTIONS TO CHANGE THAT BEHAVIOR

Although research in the area of food waste, particularly at the consumer level, is expanding rapidly, there remains a need for research to better understand the drivers of consumer waste within the food system and how that understanding can be translated into effective interventions. The current momentum to make rapid progress in preventing consumer-level food waste is hampered by a lack of well-designed and -executed studies of the effectiveness of interventions that can contribute to that progress. Further,

to support decisions about selecting and prioritizing such interventions, it will be necessary to evaluate outcomes that include not only effects on food waste but also other effects (positive or negative) that may be unintended. The effects of the COVID-19 pandemic on the food system and consumer behavior will also need to be factored into future studies and will likely generate new research questions as well.

Needed Research on Drivers of Consumers’ Food Waste Behavior

As in the research on behavior change, the committee did not conduct an in-depth literature review, but relied mainly on systematic reviews to examine the literature related to drivers of food waste at the consumer level. We synthesized information on drivers related to away-from-home discards from the peer-reviewed academic literature since we could find no systematic review in this area. The topics suggested below are meant to address the limitations of existing research and inspire future research on the drivers of food waste. Advances in this area are important because they will help in improving current interventions and designing novel interventions to reduce food waste at the consumer level.

Understanding Consumers and the Food Environment in the United States

Further understanding of consumers and the U.S. food environment is needed in the following areas:

• Explore consumer segmentation regarding food waste behaviors and attitudes so that interventions can be targeted. Particular attention is needed to research investigating such behaviors and attitudes among consumers with low income because of the lack of current data and the need for research methodologies, such as ethnographic methods, that would reach these consumers.
• Assess the benefits of reducing food waste for the different sectors of the food industry so they can be communicated to industry leaders and relevant staff. In addition, examine the upstream factors that encourage consumers’ overconsumption and identify ways to counteract these pressures.
• Identify gaps in food literacy by population groups and settings so communication and education approaches related to food waste can be tailored and designed to be more effective.
• Continue to understand the rapidly changing environment of the food industry (e.g., pandemic-induced supply chain disruptions); emerging marketing models (e.g., meal kits); and the contribution

Focusing Beyond the Individual

The effects of many correlates of food waste, such as those rooted in sociodemographic factors, likely affect food waste behaviors through the activation of other drivers, such as social norms, tool availability, or the built environment. This realization points to the importance of a systems approach, particularly the need to study interactions between drivers and socioeconomic factors. However, the literature on drivers tends to focus on the individual instead of on drivers across other contexts outside the household. Additionally, very little research has examined how behaviors and attitudes related to food waste translate across different contexts (e.g., home vs. restaurant vs. work). These contexts may activate a host of consumer goals, attitudes, and norms. For example, if it is possible to shape food waste behaviors away from home, it may be possible to design interventions that are universally useful, building new habits that consumers from many different populations and communities incorporate into their practices at home. Further, policies, such as those related to international trade and pricing mechanisms, affect the cost of food, what food is produced, how much is produced, and where. The effects of these and other policies on food waste need to be explored.

Designing Studies to Understand Causal, Correlational, and Intervening Drivers

Qualitative studies are important tools for understanding the interplay among the drivers of consumer behavior and how their interrelationships result in food waste at the consumer level. However, it is also important to understand the size of the effects of the various drivers. These two types of research complement each other. As with the literature on interventions described in Chapter 4, a shortcoming related to quantitative methods is that a large proportion of studies do not use directly measured data on the generation of wasted food. Additionally, most quantitative studies are correlational, and thus do not represent causal pathways or clarify what type of relationship a driver has with the generation or magnitude of wasted food, if any (e.g., Koivupuro et al., 2012; Setti et al., 2018). Further, to develop effective interventions, it is important to understand more precisely the relative contribution of different drivers of food waste behaviors in different populations.

Needed Research on Interventions to Reduce Consumer-Level Food Waste

The committee’s review of the intervention literature revealed multiple examples of interventions with promising results; those promising interventions can be tested further across contexts and scale, with rigorous methods, to identify best practices. Our identification of evidence gaps and limitations serves as a roadmap for the research needed to advance a set of interventions with the power to help bring widespread change. These research needs fall into two areas: methods and intervention types.

Methods

The committee identified five methodological priorities for strengthening the literature on interventions:

• Long-term follow-up evaluation of interventions, particularly for some small studies, is warranted to ensure that behavioral change is sustained beyond the initial intervention, to identify unintended consequences before scale-up, to improve tailoring to context and implementation, and to ensure that the most efficacious and cost-effective approaches are selected for continued support and scaling. The need for such follow-up is reinforced by the fact that research in the six related domains explored by the committee yielded few insights about how intervention effects persist over time (Abrahamse and Steg, 2013; Koop et al., 2019; Nisa et al., 2019; Snyder, 2007; Varotto and Spagnolli, 2017) or about to undo old and create new habits, how to prolong and reinforce newly formed habits, and how interventions may differ between those that target one-off and infrequent behaviors and those that target habits (Koop et al., 2019).
• Well-designed nonexperimental field studies (e.g., with measures of food waste, accounting for confounding factors) are helpful because they have better external validity relative to experimental studies and can be conducted for longer periods. Nonetheless, there is a need for more tier 1 studies that include appropriate control groups and other design elements to support robust causal inferences and to ensure that what is measured is actual waste reduction, rather than intentions to reduce waste. These studies would ideally leverage appropriate theory to better shape intervention design and implementation.

• Research is needed that integrates the development of interventions and implementation strategies.¹ Implementation research is essential to refine interventions—in particular, translational research that applies findings from implementation science to food waste initiatives. Also needed, however, is development of a method that pairs intervention development with implementation research. Systematic reviews in the six related domains corroborate the need to use formative research, monitoring research, and evaluative research to design interventions, monitor their implementation, and evaluate how implementation affects an intervention’s impacts (Snyder, 2007).
• As data sources and methods develop, further modeling research and other systems-oriented studies will be important. Methods for understanding multifaceted interventions are also needed. Outcomes beyond efficacy to be assessed include trade-offs, spillovers, and equity and distributional implications. In addition, more qualitative studies on interventions would allow for better understanding of the complexity of and underlying practices influencing change. The committee’s review of the six related domains revealed the lack of studies exploring underlying mechanisms, such as social norms, attitudes, and knowledge, and thus most studies cannot explain why an intervention worked or what it changed (Abrahamse and Steg, 2013; Abrahamse et al., 2005).
• The research base needs to be expanded to address diverse population groups, particularly communities with lower incomes and their contexts, and different scales.

Intervention Types

In addition to research to further evaluate the efficacy and effectiveness of interventions shown to be promising by existing studies (including those with suggestive evidence; see Table 4-2 in Chapter 4), the following types of intervention are priorities for additional study:

• interventions targeting drivers that have rarely been studied (e.g., those related to consumers’ assessment of risk, everyday complexity, influences across the supply chain) (see Chapter 4), and “strong” prevention interventions that address root-cause factors and work to shift patterns of unsustainable production and consumption; and

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¹ Implementation outcomes to be considered are acceptability, appropriateness, adoption, cost, feasibility, fidelity, and penetration.

• multifaceted interventions, implemented so as to enable segmentation of component effects in analysis.

THE SCIENCE OF IMPLEMENTING INTERVENTIONS

Implementation is an aspect of successful transformation that is frequently neglected by researchers, decision makers, and practitioners, but is essential in achieving desired outcomes. A systematic approach to implementation requires an investment of both financial and human resources. The field of implementation science is well established in such areas as education and health. As the committee’s assessment of systematic reviews in environmental and health-related behavior revealed, however, the field of implementation in these areas is still underresearched. In the realm of food waste, a few implementation guides exist for specific interventions (e.g., for reducing food waste in schools or for community education campaigns), but more attention is needed to the development of strategies and tools to support stakeholders as they implement food waste interventions. Given that implementation strategies are context dependent, providing strategies for each of the recommendations in this report would not be feasible. However, the following sections explain the importance of stakeholders’ systematic engagement in implementation and of their considering it essential to realizing the desired outcomes of interventions.

The Importance of Considering the Dissemination and Implementation of Interventions

A number of interventions designed to reduce food waste at the consumer level have shown positive results, and this report calls for new interventions to be developed and researched. Broadly speaking, interventions fall into a number of categories, such as programs (e.g., food waste curricula in schools), practices (e.g., reducing plate sizes), products (e.g., smart refrigerators), and policies (e.g., pay-as-you-throw) (Brown et al., 2017). As emphasized throughout the report, robust empirical evidence supporting the efficacy of food waste interventions is limited, and in the absence of such evidence, decision makers might choose to adopt a given intervention because it appears to be the best available solution to an identified problem or because the intervention has been mandated by an external party. Furthermore, even an intervention with empirical evidence of efficacy within a controlled experimental environment or in a given setting may not be effective in other settings. Regardless of the strength of evidence supporting an intervention, the approach used to disseminate information about the intervention and the strategies used to implement it will affect its rate of diffusion and the effectiveness of its implementation.

Given that the evidence for most interventions targeting food waste is not well developed, it is likely that new interventions will continue to be developed, and existing interventions may be redesigned. Considering dissemination and implementation issues when designing interventions can help prevent the development and testing of interventions that are unlikely to be disseminated and adopted in practice. The importance of doing so has been highlighted by implementation researchers in other fields. For example, the concept of “designing for dissemination”—defined as “an active process that helps to ensure that public health interventions, often evaluated by researchers, are developed in ways that match well with adopters’ needs, assets, and time frames”—responds to evidence about the ineffectiveness of passive dissemination approaches, the importance of engaging stakeholders in the design process, and the need to tailor dissemination activities to specific audiences (Brownson et al., 2013, p. 1695). Similarly, principles of “user-centered design”—such as active user participation throughout the project, early prototyping, and multidisciplinary design teams—have been applied to guide the development of information systems and technologies, as well as various types of interventions (Gulliksen et al., 2003). Applying similar design principles to interventions aimed at reducing food waste could be particularly important for achieving desired benefits across population subgroups.

Deciding Which Interventions to Disseminate or Implement

A community, organization, or individual may face multiple problems that could be addressed by interventions. In most cases, food waste would be one of many competing priorities, and reducing consumer food waste in one area could affect operations in another area. In addition, for any given problem, multiple possible solutions (interventions) likely exist. In some cases, there is insufficient evidence (or knowledge) to determine the optimal way to address a problem. Alternatively, evidence may exist that supports multiple solutions (interventions), leaving decision makers to select which is the best fit for addressing the identified problem. In all cases, simply selecting an intervention is not enough. In fact, as highlighted throughout this report, interventions commonly need to be adapted because some of their components or features are not applicable to the local context (Strauss et al., 2013). For example, educational content may need to be added, removed, or altered to account for the needs of different populations and to ensure cultural appropriateness (Escoffery et al., 2018). Guidance exists for planning and documenting such modifications to support research and evaluation efforts for modified interventions (Wiltsey Stirman et al., 2019).

Barriers to and Facilitators of Implementation

Once an intervention has been selected, additional work is needed to help ensure that it will lead to the desired results, such as a reduction in food waste. Just as multiple factors (i.e., drivers) contribute to food waste, various factors can influence whether an intervention aimed at reducing food waste is adopted and ultimately implemented effectively. These factors can serve as either barriers or facilitators and may occur at multiple levels, such as the intervention, the individual, the organization, and the external environment. For example, the evidence supporting the intervention, the complexity of the intervention, and its cost all may influence whether decision makers adopt it. Furthermore, perceptions of the intervention may be influenced by how information about such characteristics is communicated—by whom, by which methods, and with what content (Damschroder et al., 2009; Rogers, 2003).

At the individual level, such characteristics as the person’s role, prior experience, and knowledge about the intervention can shape perceptions of its appropriateness and, ultimately, whether decision makers choose it (Damschroder et al., 2009). Within organizations, various factors may contribute to (or hinder) the adoption of an intervention and the effectiveness of its implementation once it has been selected for adoption. For example, an organization’s readiness for change—its collective willingness and ability to implement an intervention—can be expected to influence the extent to which the members cooperate with each other during the implementation process and persist despite implementation challenges (Weiner, 2009). Similarly, a strong “implementation climate” within an organization—the extent to which use of an intervention is expected, supported, and rewarded by leadership—is expected to promote more consistent, high-quality use of the intervention (Weiner et al., 2011). Finally, in the external environment, such factors as policies, incentives, and interorganizational relationships may affect the adoption of an intervention and the effectiveness of its implementation (Damschroder et al., 2009).

Selecting and Tailoring Dissemination and Implementation Strategies

Widespread adoption of an intervention may not occur absent dissemination strategies designed to communicate information about the intervention and promote its adoption (Bero et al., 1998). These dissemination strategies can be categorized as (1) developing messages and materials and (2) distributing those messages and materials for specific audiences (Leeman et al., 2017). Once the decision has been made to adopt an intervention, its intended users typically need support to promote effective implementation.

Implementation strategies provide this support and are “the ‘how to’ of implementation efforts” (Waltz et al., 2019).

More specifically, implementation strategies can be seen as “methods or techniques used to enhance the adoption, implementation, and sustainability” of an intervention (Proctor et al., 2013, p. 140). They are intended to address barriers to adopting and/or using an intervention and may be carried out by actors other than those targeted by the intervention (Powell et al., 2015). If used effectively, these strategies help ensure that well designed interventions yield the expected benefits. Examples of such strategies include (1) holding meetings for specific stakeholder groups to teach them about the intervention; (2) forming a learning collaborative consisting of groups of organizations attempting to implement the same intervention; and (3) auditing and providing feedback about performance data so users can better monitor, evaluate, and modify their use of the intervention (Powell et al., 2015).

In the food waste context, organizations might pay attention, for example, to the many waste-producing behaviors of their members and how they are embedded in routine practices and habits. As a result, they might intervene to break the habit cycle and support the development of new food use routines during “teachable moments” when new practices are being formed. For example, higher education institutions might provide storage tools, refrigerator and freezer access, and information as part of move-in kits and establish norms via visible waste reduction campaigns in university food service facilities. Hospitals and postnatal care organizations might offer tools and incentives to help new mothers maximize the value from food as they establish new routines. Neighborhood organizations might introduce new residents to food stewardship when new residents move in, along with cues placed close to points of consumption and disposal regarding the neighborhood’s shared commitment to waste reduction. Employers might welcome new employees with storage containers and information about in-workplace storage tools and options. Agencies, nongovernmental organizations, and educators might initiate campaigns on holidays, at the beginning of the week or month, or on “special days” to capitalize on “fresh start effects.” And parent-teacher organizations might provide food use toolkits to incoming students and their families.

Just as interventions effective in one context need to be adapted to a different local context or setting (e.g., hospitals vs. schools), barriers to using an intervention may vary across different groups and settings (Mittman, 2012). This variability may necessitate the use of different combinations of implementation strategies to address those different barriers and/or tailoring of a specific implementation strategy (Powell et al., 2019). For example, communities may vary in terms of the presence of supportive policy, infrastructure, and citizen awareness related to food waste. Some

communities may need strategies targeting barriers within each of these domains, whereas others may need to focus strategies on a subset of the domains. Examples of specific strategies that may need to be tailored include the method for distributing educational materials (e.g., in person, by mail, or online) or the particular indicators monitored when auditing and providing feedback on behaviors or practices. Guidance for selecting and tailoring implementation strategies is available, and the knowledge base in this area continues to grow (Powell et al., 2017). The need to select and tailor interventions and implementation strategies illustrates some of the principles underlying the recommendations in this report, for example, that not all consumers are already highly motivated to reduce food waste and that underlying differences in household characteristics influence the amount of waste generated.

Identifying Implementation Outcomes

Given that the effectiveness of implementation influences the extent to which desired outcomes (e.g., a reduction in wasted food) are realized, it is important to select implementation strategies that address barriers to and therefore promote more effective implementation. The effectiveness of implementation can be evaluated based on implementation outcomes, which are distinct from the desired outcomes of the intervention. Implementation outcomes are “the effects of deliberate and purposive actions to implement new treatments, practices, and services” and serve as indicators of the success of implementation and as key intermediate outcomes (Proctor et al., 2011, p. 65). A commonly used framework identifies eight implementation outcomes: acceptability, appropriateness, adoption, cost, feasibility, fidelity, penetration, and sustainability (see Table 6-1).

Given the limited evidence for food waste interventions and their implementation, future research in the field could benefit from using hybrid effectiveness–implementation designs to assess both intervention outcomes and implementation barriers, strategies, and outcomes. Such a hybrid design allows for assessment that is appropriate given the current state of evidence for the interventions and their implementation. More specifically, a hybrid design follows one of three paths: (1) testing effects of an intervention while secondarily collecting information about implementation (e.g., barriers to implementation), (2) dual testing of the intervention and an implementation strategy (or strategies) for the intervention, or (3) testing of a discrete or multifaceted implementation strategy while also assessing the intervention’s effect to determine whether intervention outcomes differ relative to prior evidence (e.g., from efficacy trials) (Curran et al., 2012).

TABLE 6-1 Implementation Outcomes

General versus Intervention-Specific Capacities

Although the issues discussed above relate to the implementation of a specific intervention, it is important to consider that communities, organizations, and even individuals may have both a general and an intervention-specific capacity for change (Wandersman et al., 2008, 2015). In other words, potential adopters of interventions (e.g., communities, organizations, individuals) can vary both in their ability to make changes in general and in their willingness and ability to make a specific change (i.e., to implement a particular intervention). For example, an organization with a culture supportive of innovation, engaged leadership, robust information and communication systems, effective planning processes, and systematic quality monitoring and improvement processes may be viewed as having a high level of general capacity for change. Examples of strategies for increasing general capacity within an organization include training, technical assistance, and peer networks (Leeman et al., 2015). Although a high level of general capacity provides a supportive environment for the implementation of any specific intervention, it does not guarantee the success of its implementation (Leeman et al., 2017). Thus implementation strategies (as discussed above) are likely needed to facilitate effective implementation of any specific intervention. At the same time, however, having a general capacity for change may be foundational for selecting and tailoring the implementation strategies needed to promote successful implementation of an intervention. Therefore, it is important to consider (and increase as needed) both the general and the intervention-specific capacity for change.

SUMMARY AND CONCLUSIONS

Research evidence is vital for identifying promising interventions, but implementing them on a broad scale requires attention to other factors as well. There is a rapidly developing body of research on the implementation of interventions designed to meet public policy objectives. However, relatively little of that research has addressed food waste specifically. Efforts are needed to align the development of food waste interventions with activities to disseminate and implement them.

CONCLUSION 6-1: Implementation of interventions identified as promising requires careful attention not only to unexpected outcomes but also to such factors as feasibility, capacity, fidelity to the intervention design, cost, and appropriateness to the settings in which an intervention will be used. Translational research is needed to apply frameworks, methods, and existing evidence from implementation research to food waste initiatives.

CONCLUSION 6-2: Many interventions that have been studied have demonstrated significant efficacy in reducing food waste at the consumer level in experimental settings. However, few of these promising interventions have been systematically evaluated for effectiveness in real-world and large-scale applications. Interventions that demonstrate high levels of efficacy and effectiveness are needed to significantly reduce consumer-level food waste. Research integrating intervention development with implementation research is needed to identify and refine the most promising interventions so they can be put into practice at a broad enough scale to have meaningful effects.

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