For the first time, the Raleigh-Durham television market is the top market in the state.

The "Designated Market Area" rankings published last week list the Raleigh DMA as the 24th largest in the nation. Raleigh passed the Charlotte DMA, which is now listed as 25th largest.

Raleigh rose one spot from the 25th position a year ago, while Charlotte slipped two spots from its former 23rd ranking.

Why does it matter? Because DMA rankings are used to identify TV stations that attract the most viewers in given areas.

Brad Ransome, a general manager of media sales for Time Warner Cable, said the rankings influence advertising sales. The bigger the market, the more likely its viewers are to see large national advertising campaigns.

The rankings also can affect how Nielsen Media Research measures television ratings in a market.

"Nielsen typically invests in better technology in bigger markets," Ransome said. "This is not a Local People Meter market, but it probably should be now that it's a Top 24 market."

Local People Meter measurements are a more accurate way of determining ratings for TV shows. It's an electronic way of seeing what people are watching as they watch it, and it's the method usually used in big markets such as New York and Los Angeles.

The Raleigh market now uses less-sophisticated set-top TV meters. By contrast, the Wilmington market (DMA ranking 132) uses handwritten diary meters that residents have to fill out.

Nielsen estimates the number of TV homes in the Raleigh-Durham DMA will grow from 1,131,310 in 2011 to 1,143,420 in 2012.

brooke.cain@newsobserver.com or 919-829-4579