New York City September 10, Democratic Primary

• NYC Comptroller: Siena's mayoral poll for the New York Times also included a section about the Democratic primary for comptroller (PDF), but in this case, unlike Quinnipiac and Penn Schoen Berland, they still see ex-Gov. Eliot Spitzer with a big lead over Manhattan Borough President Scott Stringer. Siena has Spitzer up 50-35, an increase from his 44-35 edge in early August; Quinnipiac, of course, saw things move in the opposite direction. So what could account for the difference? Well, Siena was in the field for a very extended period, polling from Aug. 19 through 28. That's probably about twice as long as you really want, especially when you're this close to Election Day (Sept. 10). Though the Times defended the lengthy exposure as necessary for "good work," this sort of methodology can blur late movement, especially since Stringer only started airing TV ads just a few days before Siena began polling. (HuffPo Pollster explains why it likely took Siena so long.) On the other hand, most earlier polling (including from Quinnipiac) has given Spitzer wide leads. In the previous Digest, I was ready to conclude that Quinnipiac's mid-August poll that had Spitzer up by 19 was the outlier, but perhaps it's the other way around.
• NYC Mayor: The Bill de Blasio surge continues, with two more polls showing the public advocate on top in the Sept. 10 Democratic primary—and City Council Speaker Christine Quinn floating down to third place. Siena (PDF), on behalf of the New York Times, finds de Blasio at 32, with former Comptroller Bill Thompson at 18 and Quinn just behind at 17. At the beginning of August, the picture was reversed: Quinn 25, Thompson 16, de Blasio 14. Meanwhile, Penn Schoen Berland (for amNewYork and News 12) also puts de Blasio in the lead, though by a smaller margin. He beats Thompson 29-24, with Quinn all the way back at 17. This is PSB's first poll of the race, though, so we don't have trendlines. Also note the different field periods: PSB conducted its poll from Aug. 22-27, while Siena (as discussed above) took 10 days to finish, surveying from Aug. 19 to 28.