Politics commands a fervent, if small, following among cable viewers, many of them political professionals.

Essentially that means that cable viewers tend to watch for a while and then go on to something else.

The Arbitron ratings, which do not include cable viewers, nevertheless provide an indication of audience loss.

Reaching cable viewers is not always simple; there may be 10 or more cable systems in a single metropolitan market.

But some consultants are still not satisfied with the information available on cable viewers and on which systems sell local ads.

Request TV was available to only cable viewers at first.

Most cable viewers still watch analogue because no set-top box is necessary.

By 2012 40% of cable viewers have switched to digital.

"The undeniable result; higher rates for cable viewers," he said.

And it is all but impossible for the average cable viewer to get comprehensive schedule information.