Traditionally, when companies wanted to advertise that consumers preferred their product over another product, the companies would substantiate their claim by running a survey. Consumers would be stopped in a mall, called, or contacted online, and asked their opinions. Now that many consumers freely post their opinions online, though, some companies are wondering whether they can simply base preference claims on those opinions. Perhaps, but it’s easier said than done.

We’ve posted about one company’s attempts to support a “most recommended” claim and a “more 5-star online reviews” claim based on online reviews. In each of the cases, the NAD expressed concerns with the advertiser’s methodology and questioned whether the evidence was reliable. Now, a recent case involving Vapore’s “more 5-star reviews than any other steam inhaler” claim illustrates the NAD’s continued concerns in this area.

Vapore based its claim on a snapshot of reviews on various websites. The NAD was satisfied with parts of the company’s methodology. For example, Vapore had taken steps to ensure the data was comprehensive and that the reviews were from verified purchasers. However, the NAD had other concerns. For example, the NAD worried that Vapore didn’t account for potential double-counting of reviews across sites. And it noted that some of the reviews were dated and may no longer be accurate.

The NAD has shot down several attempts by advertisers to use crowd-sourced data to support claims. That doesn’t mean it’s not possible to make a claim based on consumer reviews, but advertisers face an uphill battle when it comes to convincing the NAD that they’ve controlled all of the variables that could affect the reliability of the data.