In the ongoing battle of advertisers in the wireless service provider industry, AT&T scored a victory when the National Advertising Division (NAD) recommended that T-Mobile discontinue the claims in the statements “T-Mobile is America’s Best Unlimited Network” and “Welcome to America’s best unlimited network.”

AT&T argued that consumers could reasonably interpret the claims to mean T-Mobile has the best overall network along all relevant metrics for customers with unlimited plans, and that T-Mobile lacked support for such superiority claims.

T-Mobile countered that in the mobile wireless marketplace, the word “unlimited” is clearly meant to qualify the claims. In the industry, any “unlimited” plan is one that offers unlimited high-speed data, a claim that the advertiser attempted to back up with data from OpenSignal and Ookla to demonstrate that its data speeds were the best.

It also argued that even if the NAD factored in other aspects (such as coverage or reliability) of a network, the difference between T-Mobile and its competitors is so small that it is not consumer-relevant and cannot outweigh the difference in speed.

Noting that the “unlimited” claims appeared “prominently” in online banner advertising, television ads and online videos, and on the advertiser’s website, the NAD recommended that T-Mobile discontinue the challenged claims.

The “Best Unlimited Network” claim “could reasonably be understood by consumers as a general network superiority claim for mobile services that offer unlimited plans of any sort, including unlimited data, talk, and/or text,” the self-regulatory body wrote. “NAD noted that the claim could reasonably convey the message that such superiority is achieved by T-Mobile across metrics for all the primary uses of mobile networks. There is no express limitation in the advertising—it does not state that the claim is about T-Mobile’s superiority in high-speed data. As a result, consumers may reasonably understand the claim to apply to all uses of their devices.”

Talk or text services provided on T-Mobile’s network are also unlimited, the NAD said, and the word “unlimited” is not exclusive to high-speed data. “While high-speed data usage is, for an increasing proportion of consumers, the primary use of mobile networks, it is by no means the only consumer relevant ‘unlimited’ use of mobile devices and networks,” according to the decision. “Further, there was no evidence that consumers’ understanding of the term ‘unlimited’ excludes their use of unlimited talk and text services.”

In addition, the NAD found that even if it accepted T-Mobile’s application of the word “unlimited” only to the message that it has the best network for high-speed data, the claim would still convey a message that its network is broadly superior to that of all of its competitors across numerous metrics relevant to unlimited high-speed data consumers—a claim for which it similarly lacked support.

In rejecting T-Mobile’s argument that its superiority in data speed is so great that it overcame any disparities in other network measurement categories, the NAD concluded that the Ookla and Open Signal evidence “does not match the breadth of the ‘Best Unlimited Network’ claim.” “[T]here is no evidence that, for consumers, speed outweighs coverage or reliability in evaluating a network,” the NAD said. “In fact, T-Mobile and its competitors regularly highlight their coverage in advertising, suggesting that all industry participants recognize that coverage is important to consumers.”

In its advertiser’s statement, T-Mobile maintained that “the network testing and other evidence submitted in this case more than supports” the “Best Unlimited Network” claim, and said it will appeal the NAD’s decision.

To read the NAD’s press release about the decision, click here.

Why it matters: The NAD recognized that the “highly competitive” nature of the wireless service provider industry leads to claims like “fastest,” “largest,” “best coverage” or “most reliable” by various advertisers. “While wireless service providers should be free to truthfully tout the advantages that their innovations provide consumers, these comparative advertising claims must nonetheless be substantiated in order to avoid misleading consumers and to ensure that wireless service providers compete on a level playing field.” With this background, the NAD determined that the “Best Unlimited Network” claims conveyed a broad overall network superiority message and not a qualified claim about high-speed data, a message that T-Mobile failed to substantiate.