Friday, September 12, 2008

State and National Polling Post-Convention

The gains of the Republican ticket continue in both state and national polling as more post-convention state polls become available. We now have 26 states with a post-convention poll and the results mirror the sharply pro-Republican movement seen in national polling since Sen. McCain's acceptance speech.

The McCain lead is now about 3 points in national polling and is just under 4 points for those states with post-convention polls.

An important point is that the states with post-convention polls are not a representative sample of all states, though the differences between states without a recent poll and those with new polls is not large. States without new polling have averaged 2.1 percentage points more pro-Obama than those states with new polling. However, if we plot the trend lines in the chart for all states (with or without new polls) and for those with post-convention polls, we see the two trends have followed similar if not identical trajectories.

Since our last update of this comparison of state and national trends the addition of new states has brought the state trend line a bit below the national polls trend, something not so visible in the earlier post. This difference reflects the selection of states that have new polling, rather than shifts in the vote margin in the states, except of course for the brand new polls.

The bottom line is that the swing towards the Republicans remains strong in both state and national polls , amounting to a 7 point national swing and a 5 point swing based on the state polls. In an earlier post, I pointed out
The bottom line is neither campaign should be complacent or despondent. There is a lot of time left and recent history shows that both up and down swings of 6-9 points are entirely plausible.
Right now that magnitude of swing is looking about right.

The states with post-convention polls are: Alabama, Alaska, Colorado, Florida, Georgia, Idaho, Maine, Maryland, Michigan, Mississippi, Missouri, Montana, Nevada, New Hampshire, New Jersey, New Mexico, North Carolina,North Dakota, Ohio, Oklahoma, Pennsylvania, Virginia, Washington, West Virginia, Wisconsin, Wyoming.