The stated goal of the study is to evaluate the effectiveness of three disclaimer schemes for conveying information to consumers about emerging scientific evidence about certain diet-disease relationships. Each of the schemes is evaluated against three performance standards: (1) the ability of disclaimers to mitigate consumer perceptions of the level of scientific evidence for a claim as compared to an unqualified claim; (2) the ability of disclaimers to convey distinct levels of scientific evidence for health claims; and (3) the impact disclaimers have on other measures of product assessments, including health benefits, as compared to an unqualified health claim and a no-claim control.
For the first standard, none of the schemes is entirely successful at exhibiting appropriate disclaimer effects vis-à-vis scientific evidence for a claim as compared to an unqualified claim. Across the three schemes, for both foods and dietary supplements, C and D-level disclaimers elicit appropriate effects on ratings for scientific evidence from respondents. However, B-level disclaimers are often ineffective at reducing ratings for scientific evidence. This is particularly evident in Scheme 3, where the B-level claims has no effect on foods, but has a significant and positive effect on dietary supplements, the opposite from the desired effect
Against the second standard, none of the schemes is completely successful. Although the results indicate that all three schemes exhibit some ability to convey distinct levels of scientific evidence, there are instances in each of the three schemes where ratings for scientific evidence do not differ significantly between claims of adjacent levels. In the current scheme employed by FDA (Scheme 1), where health claims that have significant scientific agreement make no mention of scientific evidence for the claim, respondents do not always distinguish between A-level claims (current health claims) and B-level claims (current qualified health claims), especially for the dietary supplement products examined in this study. Neither the addition of language about scientific evidence to these A-level claims (Scheme 2) nor the addition of an “A” grade (Scheme 3) are consistently and substantively effective at enabling respondents to distinguish between A and B-level claims.
With respect to the third standard, the findings parallel those found against the first two standards. For the likelihood that the product will reduce the risk of the disease mentioned in the claim, the disclaimers in Schemes 1 and 2 have noticeable effects in the appropriate direction for D-level claims only, whereas the grade disclaimers in Scheme 3 have noticeable effects in the inappropriate direction, with B and C-level claims rated significantly higher than unqualified claims.
For the likelihood that the product will reduce the risk of diseases not mentioned in the claim, only Scheme 3 grade disclaimers show any significant impact, appropriately reducing perceived likelihood. For other measures, such as importance to a healthy diet and quality, there is some evidence that A-level claims have a positive impact and D-level claims have a negative impact on ratings across the three schemes, particularly for dietary supplements. However, the study finds no significant impact of any claim/disclaimers on consumer perceptions of product safety.
Each of the schemes exhibits some level of success and some level of failure against the three performance standards. None of the schemes should be deemed entirely effective at conveying the intended levels of scientific evidence supporting health claims. Although the schemes show effectiveness at communicating levels of evidence for less supported (i.e., C and D-level) claims, none of the schemes is consistently capable of highlighting the distinction between claims with substantively different levels of scientific evidence: those that meet the FDA’s rigorous standard of significant scientific agreement (A-level claims) and those that do not (B-level claims).