A recent National Advertising Review Board (“NARB”) decision reminds advertisers to adhere to a fundamental principle of product testing: competing products should be tested in accordance with their usage instructions to substantiate comparative claims.

The September 8, 2015 decision involved a Clorox advertisement showing side-by-side white t-shirts with large spaghetti stains. One shirt was treated with the advertiser’s Clorox Regular Liquid Bleach and the other with challenger Church & Dwight’s OxiClean White Revive. After washing, the OxiClean shirt retained some staining while the Clorox shirt appeared completely white. A super explained that the products were used “as directed through the wash.” The advertisement also claimed that “Clorox eliminates stains better than OxiClean” and that “Clorox eliminates stains better.”

Church & Dwight challenged this advertisement at NAD. NAD found that the advertisement conveyed that Clorox removes all stains, including tough stains, better than OxiClean, and that this claim lacked a reasonable basis because Clorox’s testing did not follow the OxiClean usage instructions. NAD recommended that Clorox discontinue the side-by-side t-shirt comparison and the claim that Clorox eliminates stains better than OxiClean.

Clorox appealed these findings and recommendations to the NARB, which agreed in nearly all respects with NAD’s decision.

As a general matter, the NARB panel stated that the most reliable measure of a product’s performance involves testing the product in accordance with its manufacturer’s instructions for use. The instructions on packages of OxiClean White Revive were organized into three sections:

• First, a section entitled “Add to Every Load to Remove Stains & Maintain Brilliant Whites” instructed consumers to add in ¼ scoop of OxiClean or “more for large or heavily soiled loads.”

• Second, a section labeled “Pre-Soak to Remove Tough Stains & Revive Dingy Whites” directed consumers to pre-soak laundry for 1-6 hours—with half a scoop of OxiClean for “typical” stains and 1 scoop for “dingy whites and extra tough jobs.” Consumers were then instructed to “wash as normal.”

• Third, under the heading, “For Best Results,” consumers were instructed to pre-soak “heavily stained or soiled loads” for 6 hours.

The NARB panel, echoing the NAD decision, found that because most consumers would reasonably classify the large spaghetti stains in the side-by-side t-shirt comparison as “tough,” Clorox should have tested OxiClean in accordance with its use directions for tough stains—i.e., with at least 1 hour of pre-soaking. Because none of Clorox’s studies had tested OxiClean with a pre-soaking step, NARB recommended that Clorox discontinue the challenged advertising.