One of the oddities of television news closed captioning is the way in which strange inconsistencies can arise in captioning presence across an ad's runs. For example, take the closed captioned PSA "No Time For Flu" by the CDC, AMA and Ad Council. In some occurrences it appears with closed captioning, while in others it appears uncaptioned, meaning those dependent on captioning are unable to understand what the ad is about. Even stranger, some airings include captioning errors like "momfor thoseall just trying whchef" while others have flawless captioning.
You can see the variations of the captioning of this particular ad across its run late last year.
Such oddities are seen across the major channels, across programs, days and times, suggesting this "captioning loss" represents a broader obstacle to accessibility. Many questions remain, such as at what stage in the broadcast pipeline captioning is lost, what explains the introduced errors not present in the original captioning and so on, all of which are areas of future research. It is clear that of the 2/3 of all television advertising each day that is uncaptioned, not all of that content began life uncaptioned – some of it may have been captioned when originally submitted for broadcast and lost its captioning somewhere along the way.
At the end of the day, however, the loss of captioning for public health PSAs in the midst of a global pandemic means this critical messaging is inaccessible to a portion of the American public, suggesting this captioning loss is a critical obstacle to public messaging.