How It Works
For campaigns, ads are must-see TV
Cost of buying commercials means ads are carefully targeted
WASHINGTON (CNN) -- Television advertising is the biggest single expenditure of a presidential campaign, a way for candidates to beam a message straight into living rooms without interference from the pesky press.
But ads -- whether they're focusing on Medicare or national defense -- work only if the right voters are watching.
That's why campaigns try to target their political TV ads to the audience watching a particular show.
But it doesn't always work out that way.
"There are many examples when we look at ad buys unfold when ads that are clearly aimed at senior citizens are showing up on programs like "American Idol" and "The OC" on Fox that tend to skew very young," said Evan Tracey, an analyst who tracks political ad spending.
Campaigns, Tracey said, can get caught up in a kind of advertising arms race, competing with each other to buy time on programs with high ratings among likely voters.
But ratings don't matter if the right voters aren't tuning in, meaning that an ad that critiques a candidate's position on Medicare would be lost for the most part on a television show that targets a young audience.
"Those ads are essentially wasted, unless someone sees them by mistake, when they're flipping channels," Tracey said
So look for health care and education themes during the day, when seniors and stay-at-home moms are watching, and economic messages in the evening, as folks get home from work.
Don't expect to see much of anything if you live in, say, Vermont. Campaigns pump advertising dollars into battleground states like Ohio and Pennsylvania.