Nielsen's preliminary collective household rating was a 38.3 on Wednesday night, down from the 42.1 rating for debate number two but higher than the 34.7 number of the first encounter.
Competition for viewers may have been a bit higher--given Fox's League Championship series game between the Philadelphia Phillies and Los Angeles Dodgers--a decisive game that gave the Phillies the victory, sending them to the World Series. In addition, Nielsen says the size of both markets played a role; Los Angeles and Philadelphia are the second- and fourth-largest TV markets, respectively.
In household ratings, however, Nielsen reports that Baltimore, Washington, D.C. and St. Louis had the highest ratings, with New Orleans, Los Angeles and Sacramento, Calif. the lowest.
The three broadcast networks collectively pulled in 28.9 million viewers for the 90-minute debate that ran from 9 p.m. to 10:30 p.m. The best performance this time went to NBC, after ABC earned higher ratings for the first two.
NBC averaged 10.34 million viewers (a 7.8 household rating/12 share), ABC 9.66 million (a 7.5/11), and CBS 8.9 million (6.1/9). PBS pulled in 3.2 million (2.1/3), its best performance among all three presidential debates. (The lone vice presidential debate earned 3.5 million viewers on PBS.)
While Fox aired the first two presidential debates and the one veep debate, it took a pass on the event last night to air a more pressing baseball playoff contest. That game looks to average, preliminarily, around a 3+ rating among 18-49 viewers.
NBC ended up earning first place for the night among 18-49 viewers, with a 3.2 rating/8 share; ABC was at 2.5/6, CBS and Fox tied for third at 2.4/6, Univision fifth at 1.4/3 and CW sixth at 1.0/3.
Early in the evening, NBC gained a little bit for its struggling new drama "Knight Rider" versus a week ago, with a 2.4 rating at 8 p.m. For its new show of the night, CBS earned a 2.4 rating for "Gary Unmarried" at 8:30 p.m. ABC struggled at 8 p.m. with its second-year show "Pushing Daisies," which earned a 1.9 rating.