LITERATURE REVIEW METHODOLOGY

Approach to Literature Review

The following section discusses the literature on consumer use of and preferences for FOP symbol systems. The committee limited its review to literature that directly examined FOP symbol systems, was published in the United States and Europe, and covered a search period from January 2000 to June 2011. The committee included studies published prior to 2000 at its discretion. Chapter 4 discusses the literature on use of the Nutrition Facts panel (NFP), and Chapter 6 discusses the literature on consumer response to aspects of labeling, including health claims, package clutter, and related themes. Appendix D provides a complete description of the committee’s approach to its review of peer-reviewed published literature.

Types of Front-of-Package Symbol System Studies Examined

The committee used a hierarchy to categorize studies of FOP symbol systems, ranging from studies that are most likely to provide the best insight into how consumers might respond to a particular FOP symbol system to those that provide a lesser quality of evidence or are associated with greater uncertainty. Studies published in the peer-reviewed literature are at the top of the hierarchy. Within this group, field or natural experiments were given the greatest weighting. Field experiments examined implementation of an FOP symbol system in “real-world” settings and assessed their effects with objective outcomes such as changes in sales data. Although these studies are limited in number, their results are most likely to reveal how FOP systems might influence consumer choice if implemented.

Peer-reviewed studies reporting randomized designs provided the next level of evidence. These studies randomized subjects to view one (or several) variants of a FOP label, either in a research space, outside a supermarket, or online, and compared reactions across the experimental conditions on a variety of outcomes, including consumer choices, perceptions of product healthfulness, and overall preferences for FOP systems. Table 5-1 summarizes examples of field experiments and randomized design studies.

The committee then considered the applied marketing research literature that was either sought out or provided to the committee. Because it had not been subjected to a peer-review process, this work, positioned at the lower tier of the hierarchy, was given substantially less weight in the committee’s deliberations.

Peer-Reviewed Field Experiments

The strongest evidence to demonstrate how an FOP system will operate in a real-world shopping environment comes from actually implementing the system on supermarket shelf tags or products, and observing via sales data the impact that it has on consumer food choice and purchase decisions. As the name implies, field experiments are conducted in natural settings, which may not allow for full control of the environment, but allow for a full examination of how consumers make choices in a natural or real-world setting, with all of the inherent time, cost, and other pressures. They also provide a realistic sample—consumers go to the grocery store as part of their usual shopping routine. The outcome of interest in field experiments is sales, which is a key outcome under examination by the committee. Whether there are correlations between food product sales and patterns of total food consumption and subsequent outcomes such as levels of obesity has yet to be determined. As such, studies of this type are needed to better understand the scale and scope of the effects of FOP systems on consumer behavior.

The committee identified four studies that examined differences in sales after introduction of shelf tag–based FOP systems. In the first study, Levy et al. (1985) examined whether the prominent but relatively simple display of low/reduced dietary components (according to current dietary guidance: sodium, calories, fat, and cholesterol) on a shelf tag would increase sales as a result of “shelf salience.” This program was aimed to be “more promotional than rationally persuasive.” Ten comparison stores were matched with 10 control stores. Although the results were inconsistent across product categories, the investigators found that on average sales of the labeled products were 4



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