Cross-posted from The Left Anchor...

Crian hits on some good points in his piece concerning the media's
continued concern with Obama's "poor poll numbers" (odd how the fact
that McCain hasn't led once among RVs all summer doesn't reflect poorly
on him).  Crian notes that given Obama's quick rise to prominence,
people are more likely to view him as an unknown quantity whereas
McCain's been in the public spotlight ever since he began his bid in
1999.  This is a fair point, but I also think it's important to note
that Obama is, in fact, leading, and he has been all summer long. 
Obama's five point lead has been almost unbelievably consistent.  The most recent Gallup poll has Obama at a -- you guessed it -- five point advantage over John McCain (47-42). 

Another oft-overlooked fact is that Obama has reached fifty percent support in the Gallup polls several times this summer.  McCain has yet to break 44 percent support among registered voters.  The best the McCain camp can do is point to some brief leads their candidate has enjoyed among likely voters, but historically, this far from the election polls of registered voters are likely to be more accurate than those of likely voters (the reverse is true in the closing weeks of a campaign).  This comes directly from the editor of Gallup himself, Frank Newport:

The July 25-27 USA Today/Gallup poll shows Barack Obama leading John McCain by a 47% to 44% margin among all registered voters but McCain leading Obama among likely voters by a 49% to 45% margin. This difference between registered and likely voters indicates that now McCain voters are disproportionately represented among the estimate of those most likely to vote if the election were held today.

<snip>

So, as a rule of thumb, registered voters are the relevant group to trend to establish basic patterns of change in voter support for presidential candidates. Likely voter modeling at this point is an additional analytic tool.

Even the conservative magazine National Journal views the likely voter models as suspicious, especially in light of how far off they are from the registered voter models:

Emory University political science professor Alan Abramowitz is undeterred. "A 7 point difference in [the vote preference] margin between actual voters and all registered voters," he wrote me, "would be much larger than that found in American National Election Studies surveys in any of the 14 presidential elections between 1952 and 2004 -- the largest gap in pre-election margin was 3 points way back in 1952, and the average gap was only one point."

I think he has a point. Gallup's data tells us that Obama's narrow lead among registered voters depends on those who tend to score lower on measures that typically correlate with turnout. So, not surprisingly, the Obama campaign is investing heavily in efforts to register and turn out new voters.

What is less clear is whether news accounts ought to be emphasizing such snapshots in July when the mechanism for those estimates is so inherently hypothetical and potentially shaky.

But even giving McCain the benefit of the doubt here, among likely voters, McCain has lead only twice, once by four points, and once by a single point, and the poll which put McCain at a four point lead significantly underrepresented the youth vote even by 2004 standards despite the fact that the youth vote is likely to increase this year.  Obama has carried every other likely voter or registered voter poll since the middle of May.  Moreover, Obama leads McCain in total number of field offices by nearly 3 to 1.  Effective voter outreach combined with a solid GOTV plan can add an extra two points to a candidate's numbers on election day.  The extended primary helped Obama in this sense, forcing him to organize and invest in states very early in the year, and putting him at a significant advantage over McCain.

To put it more bluntly, Obama is leading.  He has the better ground operation, and it's probable that the likely voter polls are filtering out many of Obama's supporters (the youth vote), while overrepresenting likely McCain voters (the elderly).  And yet, Obama is still leading.

As always, recs greatly appreciated.