NEW YORK: Media fragmentation has triggered a rapid expansion in 15-second TV commercials in the US, as advertisers use brevity to get their messages heard.

The number of 15-second TV ads has jumped more than 70% in the past five years, says Nielsen, now accounting for some 34% of all the ads aired nationally last year.

Kantar agrees, estimating that more than half of all  commercials run by packaged-goods companies - and as many as 60% of fast-food ads - are now in the 15-second format.

Although these shorter ads were once edited versions of 30-second spots, advertisers are nowadays using them as stand-alones.

The spots are designed to remind consumers about specific products, stores or prices, rather than introduce them to brands, according to Kantar.

Procter & Gamble doubled its number of 15-second ads to more than 299,000 last year while Walmart, the world's largest retailer, has increased its use of shorter commercials from around 5,700 in 2005 to 148,000 last year.

The latter firm also plans to air even more this holiday season.

In terms of price, shorter ads cost about the same per second as their longer cousins, with a 15-second ad on network TV weighing in at around $20,000 (€14,400; £12,500) on average last year, according to Nielsen.

"It becomes a very seductive thing to get your message out there at half the cost," says Mike Sheldon, CEO of advertising agency Deutsch LA, a unit of Interpublic Group.

On average, some 5% of an audience exposed to a 15-second commercial will turn over or walk away before it finishes.

That number jumps to about 6% for a 30-second spot and 6.5% when the ad is 60 seconds long, says Jeff Boehme, chief research officer for Kantar Media.

Data sourced from New York Times; additional content by Warc staff