(Updated 9/24/2014, 11:20 am)

In the Philadelphia area, most candidates and campaign committees trying to woo voters with TV ads this election season are going out of their way to reach out to those with hearing difficulties, but there are some notable exceptions.

Republican Gov. Tom Corbett’s campaign for re-election is most prominent of the political committees advertising on Philadelphia-area TV this fall without closed captioning, written transcripts of a broadcasts’ spoken words that can be activated on most TVs.

The omission isn’t partisan however: The Philadelphia Federation of Teachers, which has bought ads opposing Corbett, also fails to provide the captions. So does the campaign of Tom MacArthur, a Republican running for an open congressional seat in south Jersey.

The findings were unearthed as part of the Philly Political Media Watch, a pilot research project by the Internet Archive, the Sunlight Foundation, the Committee of Seventy and local scholars to catalogue political communications and trace funding for them to the source.

Our initial efforts focus on advertising in one of the nation’s largest TV markets during the 2014 campaign. The Internet Archive, which is capturing Philadelphia TV broadcasts on servers housed at the University of Pennsylvania’s Linguistics Data Consortium, noticed the omitted captions because the Archive uses them to index the TV data.

While the Federal Communications Commission requires closed captioning on most television programming, advertisements are generally exempt. Most advertisers provide the captions, however, to expand their market reach. In a December 2010 memo to members, the Association of National Advertisers extolled the benefits of closed captioning, noting that the “cost . . . is minimal” and that it would enable advertisers to reach an estimated 36 million Americans who suffer from hearing loss (low, according to Johns Hopkins University, which puts the number at 48 million).

Corbett’s campaign said that “some” of the governor’s ads are closed caption “but not all.”

Corbett’s media consultant, John Brabender, told Sunlight in an email that the campaign tries to used closed captioning when it can, but that the need for rapid response sometimes makes that impossible. Brabender said he’s confident voters get the message even without closed captions: “There is often continuous type in the ad and the point of the ad is still very clear,” he wrote.

“That’s really patronizing,” retorted Christian Vogler, director of the Technology Access Program at Gallaudet University, which caters to students who are deaf or hard of hearing. “It’s not about being clear; it’s about equal access,” Vogler wrote in an online chat with Sunlight. As far as the need for rapid response, Vogler said it’s a problem that television producers successfully handle every day. He supplied a list of companies that provide close captioning services, which he called a growing field.

“There’s no real excuse” for advertisers not to use closed captions, Vogler said. “If there is sound in an ad, it needs to be closed captioned, no matter how clear the visuals may be.”

So far in its analysis, the Internet Archive has not found any Corbett ads in the Philadelphia market with closed captions.

The Sunlight Foundation has contacted all of the organizations that the Internet Archive identified as not using closed captions for explanations as to why they omit them. We will update this blog post if and when they respond

The National Association of Broadcasters said it pulled a political ad that it had been running in Pennsylvania after two days when it realized it lacked closed captioning and gave TV and radio stations a new spot to run. The Internet Archive has yet to find captioned ads.

“We’ve always been supportive of the notion that hearing impaired or sight impaired folks had the chance to hear our spots,” said Dennis Wharton, the NAB’s vice president for communications.

Andrew Phillips of the National Association for the Deaf says that “it’s common sense to add captions,” noting that “the cost of captioning is tiny compared to the cost of making and airing the advertisement.” Phillips also noted that the captions allow advertisers to reach a lot more than more than people with hearing problems. “There are many places where TVs are muted and the captions are on,” he said, “such as bars, airports, public places.”

(Contributing: Peter Olsen Phillips)