Verizon ads claiming that FiOS fiber service "is rated #1 in Internet speed" are misleading and should be changed, the National Advertising Review Board (NARB) said this week.

Verizon doesn't actually offer the fastest speeds, but the company justifies the claim based on PC Magazine’s Readers’ Choice Survey. NARB's decision—which came after a complaint filed by Comcast—noted that ranking "was not based on a comparison of objective Internet speed performance and/or a head-to-head comparison of different Internet service providers." Instead, it was based on customers' perceptions.

Verizon ads do note that the #1 claim is based on "customer satisfaction studies," but the board ruled that Verizon's ads made it seem as if the company actually offers the industry's fastest speeds.

"NARB, in its decision, noted that one of the challenged advertisements was 'fast-moving, with objective speed claims made in parts of the advertisement and a visual that prominently links the #1 rating to Internet speed rather than customer satisfaction. In this context, reasonable consumers may very well take away a message that Verizon’s #1 rating is based on a comparison of objective Internet speed performance and/or a head-to-head comparison of different Internet service providers,'" the review board said.

The board also recommended that Verizon modify its claim of superior picture quality "to more clearly communicate that the higher rating with respect to HD picture quality was a customer satisfaction rating based on consumers’ rating of their own Internet service providers."

In a similar decision in November 2014, AT&T was told to stop advertising U-verse as the "Fastest Internet for the price" or make it clear to consumers that the claim referred to a 3Mbps service, one of the slowest speeds AT&T was offering.

Verizon isn't required to follow the recommendations, but the company said it will consider them in future ads. The NARB is run by the Council of Better Business Bureaus and is the key body in the advertising industry's system of self-regulation.

Verizon FiOS top advertised speeds are 500Mbps upstream and downstream. Comcast recently began offering gigabit download speeds via cable and 2Gbps symmetrical connections via fiber.

Advertised speeds aren't always as high as actual speeds, but Comcast has outperformed Verizon FiOS in comparisons of actual vs. advertised speeds in both uploads and downloads, based on Federal Communications Commission testing in customers' homes.

UPDATE: Verizon contacted Ars with a statement, saying, “Nowhere does the NARB say or suggest that Verizon’s ads were misleading or deceptive. We’ve simply been asked us to clarify the basis for our claims. But It’s not surprising that Comcast would argue over semantics to distract from their usual poor performance in consumer satisfaction surveys. No matter how you phrase it, Verizon FiOS has the happiest customers.”

While Verizon is correct that the board did not use the words "misleading" or "deceptive," the NARB did say that the ads gave reasonable consumers a message that is different from the facts, which meets the definitions of both words.