Do you have the best wireless provider? If so, best in what sense—the best contract, the best devices, the best connectivity, the best value? That was the issue NAD recently addressed when it recommended that T-Mobile discontinue its “Best Unlimited Network” claim. AT&T challenged T-Mobile’s tagline in a recent NAD case, arguing that it was an unqualified superiority claim that T-Mobile couldn’t substantiate.

Now, the advertising world is no stranger to the word “best,” which we discussed in an earlier post on The Absolute Best Puffery Panel Ever. The problem arises when “best” is meant as a measurable claim, including its use here in connection with the phrase “unlimited network.” As NAD pointed out in this T-Mobile decision, wireless service providers should be able to tout the advantages that their innovations provide, but their claims must be substantiated to avoid misleading consumers. NAD reiterated in the T-Mobile decision that broad superiority claims (like “best” or “largest”) must be supported by reliable market data.

In this case, the parties disagreed as to how consumers understood the phrase “Best Unlimited Network.” T-Mobile argued for a narrow understanding of the phrase, saying that “unlimited” causes consumers to think of “unlimited data,” making it a superiority claim only about its unlimited high-speed data. Challenger AT&T responded that even if that were the case, T-Mobile would still have to provide reliable data showing the relative performance of each network for consumers who have unlimited plans. Additionally, AT&T argued that “Best Unlimited Network” spoke to a broad superiority claim that required T-Mobile to substantiate superiority in the various relevant attributes of its data, talk, and text mobile networks.

The NAD decision noted that T-Mobile failed to provide any evidence regarding how consumers understand the word “superiority” in this context, so NAD had to “step into the shoes of the consumer to determine the messages reasonably conveyed by the advertising.” NAD found that without an express limitation in the advertising, consumers could reasonably understand the claim to mean T-Mobile is superior in all areas (not just high-speed data). Because this might lead the consumer to believe T-Mobile’s network is superior to all others in speed, coverage, reliability, and metrics related to voice and text, T-Mobile would have to substantiate the claim in all those areas.

Unfortunately for T-Mobile, NAD found that the somewhat sparse evidence offered (speed tests from third parties Ookla and OpenSignal) did not match the breadth of the claim of “Best Unlimited Network.” T-Mobile also creatively argued that consumers value speed over all else when it comes to wireless networks so its relative advantage with respect to speed overcomes any disadvantages it may have in other network attributes. Unfortunately for T-Mobile, NAD found no evidence to support the idea that consumers value speed more. T-Mobile stated that they plan to appeal the NAD decision to the National Advertising Review Board.

In the meantime, the takeaway seems to be if your marketing people want to tout their product as the best, you might want to suggest that they also have the “best” substantiation for the claim.