Mark Blumenthal | October 16, 2008
Topics: Status Update
Before the debates (and the quick reaction surveys released late last night), the flood of new surveys continued, as we logged 22 new statewide polls yesterday, plus three new standalone national polls and the latest updates from the (now) seven daily national trackers. The pattern at the state level remained consistent with we have seen since mid-September. Of the 18 new surveys that track previous results from the same pollster, and 13 show net movement to Obama, 3 to McCain and 2 show no change. Only three of the statewide polls represent updates since early October, and all three show net shifts to the Obama-Biden ticket.
Note for rolling-average tracking polls, that the first table lists the previous non-overlapping sample for each pollster, not the release from the previous day.
The new polls affect our statewide trend estimates in two ways. They nudged the estimates in Obama's direction in six states, including a 1.3 point shift in Virginia that increased the Democrats' margin there to just over five percentage points (51.0% to 45.9%), enough to move Virginia and its 13 electoral votes to the light blue "lean Democrat" category on our map.
The current Obama margin on our national trend estimate has fluttered around over the last few days, but has remained somewhere between 7 and 9 points over last week. Keep in mind that while the forward "tail" of the trend line (a funny sounding term, but I'm not sure what else to call it) tends to jump around as we add new polls, but regression trend line smooths out as we move forward. Charles Franklin sent an update of his "national forces" chart late yesterday and it shows continuing movement over the last week to the Democrats on both the national trend and his mash-up of all state polls.
A note on the "all state polls" trendline. Franklin makes no effort to adjust or weight the state poll numbers to create a nationally representative statistic. He simply calculates the Obama minus McCain margin for each new statewide poll and plots a regression trend line through those points. The closeness of the level of "all state polls" trend to the national trend line is mostly coincidental. Theoretically, the "all state" trend could go up or down if the statewide polls over any particular period happened to be mostly from red or mostly from blue states. For the most part, the polls distribute consistently and the national poll and state poll trends generally mirror each other closely and right now, both trends continue to favor the Democrats.