Numbers raise questions about just how many opinions the debates affected, Obama's up in his crucial state of Ohio, and national polls give Romney the upper hand. Here's our guide to today's polls and why they matter.

Findings: Debates don't really have that much of an impact when it comes to how people pick their candidates. In the new NBC/Wall Street Journal poll 47 percent say the debates made no difference in how they would vote. Meanwhile, 27 percent said the debates would make them more likely to support Romney and 24 said it would make them more likely to support Obama, which just about evens the score. 
Pollster: Peter Hart and Bill McInturff for NBC/Wall Street Journal 
Methodology: Interviews with 1,000 registered voters October 17 through 20 with a +/-3.10 percent margin of error.
Why it matters: We make a lot of fuss about how debates shift the numbers, but voters say that they aren't really changing their opinions. At the Washington Post Chris Cillizza poses some theories as to what this means. One idea? The country is just very partisan right now. Another? "People don’t like to admit debates sway them." 
Caveat: Well, there's another debate tonight. 


Findings: Obama is up by five points in Ohio. 
Pollster: CBS News/Quinnipiac 
Methodology: Landline and cell phone interviews with 1,548 likely Ohio voters October 17 through 20 with a +/-2.5 percent margin of error. 
Why it matters: As our Elspeth Reeve explained this morning: Obama needs Ohio, and Obama needs women in Ohio, who in this poll support him by 15 points. As Nate Cohn at The New Republic puts it: "Ohio rests at the center of Obama's claim to an advantage in the Electoral College." This poll gives Obama a bigger lead than his Real Clear Politics average, and Cohn's assessment is that even though the contest is close "Obama's lead remains clear."
Caveat:  The team over at CBS writes that Obama is leading among early voters, but is only up by two among likely voters who haven't voted yet. They continue: "As has been the case throughout this election campaign, Ohio Republicans continue to be more enthusiastic than Democrats about voting this year." 


Findings: Romney's up in four national polls today (by six-points in Gallup, by two or three in the others) and the race is tied in two. 
Pollsters: GallupRasmussenMonmouth/SurveyUSA/BraunPolitico/GWUReuters/Ipsos, and NBC/WSJ.
Methodology: For Gallup, Rasmussen and Reuters: tracking. For Monmouth/SurveyUSA/Braun: Survey of 1,402 likely voters October 18 through 21. For Politico/GWU: Survey of 1,000 likely voters October 14 through 18. For NBC/WSJ: Survey of 816 likely voters October 17 through 20.
Why it matters: National polls appear to be giving Romney a slight advantage, other than Gallup, which is giving him a large and an IBD/TIPP tracking poll out Sunday which had Obama up by about 6. Nate Silver explains: "Although the national tracking polls show, on average, a race that is about tied, they would have conveyed the impression of a four-point lead for Mr. Romney if weighted based on how often they were cited in news accounts." 
Caveat: Silver also points out: "Mr. Obama’s swing state polls are consistent with the hypothesis that he holds some sort of Electoral College advantage, but they are also consistent with the hypothesis that the national polls have the race slightly wrong."