Over the coming months, there will be plenty of talk about what polls mean for either Romney or Obama. But polls only mean so much, and the data is often left open for interpretation by the pollsters.
For instance, today's Quinnipiac Poll shows Obama ahead by a slim 46-43%. Might sound good for Obama, but the real reason it might not be is because the poll actual weights the Republican sample to just 27%, while using a Democratic sample of 31%. As shown here, turnout in 2010 was split evenly at 35% in 2010, while Rasmussen has shown a continuing trend of Republican Party registrations, and they actually edge out Democrats currently by 36-34%. In 2002, 2004, 2006, and 2010 the average turnout was dead even,, and never has Republican dropped below 30%, much less to 27% as Quinnipiac "weights." Only 2008, which is more of an outlier than anything, showed the type of voter disparity shown here. If you use Rasmussen's current registration ID Romney is handily ahead. And if you simply use the turnout from 2010 (or 2002, 2004, 2006) Romney is still ahead, given his lead with Independents. So in reality, Obama's lead only reflects how the pollsters decided to weight the sample, which favored Democrats in an scenario unlikely to happen.
Meanwhile, Rasmussen Reports has Romney up 3-points, 47-44, and they weight according to extensive multi-month surveys and also do extensive daily tracking. Gallup also does extensive daily tracking, and they have a 46-46 tie. The two differences between the polls are that Rasmussen uses a 3 day rolling average and Gallup uses a 7 day average, while Rasmussen only uses Likely Voters while Gallup uses Registered Voters. (Polls with Registered voters have a slight Democrat bias as it includes a percentage of voters who do not plan on voting but if they did would vote for Democrats).
At the same time, a Washington Time poll of Likely Voters has Romney up by one, 43-42%, while an ABC poll of Registered Voters (again, usually naturally biased towards Dems), has a tie of 47-47%. A final outlier poll has Obama up 6%, but uses a bizarre sample of 47% Democrats, a number about 10-points higher than any election over the last decade. (Poll Roundup)
What's this all mean? Obama can't break 50% in any poll, despite assaulting Romney with every invented distraction, outspending Romney my overwhelming margins, having his "signature legislation" upheld, and being against an opponent many supposedly do not like.