Obama is Pulling Ahead in Important Swing States

by: tremayne

Mon Sep 22, 2008 at 17:25

I have argued that September 15th is an important demarcation point in recent polling of the presidential race. Based on movement in the daily tracking poll average it appeared the last day where John McCain enjoyed any remnants of his post-convention and post-Palin bounce was September 14. When that day dropped out of his average, Barack Obama moved to 3.5 point lead in the national horse race.

As many have noted, the same positive movement has not been as apparent when looking at the state polls. The main reason for this is simple; most states, even swing states, are polled less frequently. Even when a "new" state poll emerges take note of the dates when data were collected, it is often as much as a week prior. Only now are we beginning to get a full picture of what the race looks like from polls taken September 15 and on. What that data shows is Obama ahead in almost every important swing state where data is available.

Details follow.

To examine the premise outlined above, I compared state polling from the week of the McCain-Palin bounce (Sept. 8-14) to the following week (Sept. 15-21) using all the state data at Pollster.com. Again, it's not the polls release date that matters but when the polling was done. When the majority of data was collected on or after September 15 I included it in that group. When the majority of data was collected prior to September 15 I included it there. In one case the data collection was evenly split and I threw that poll out.

For some states there was no polling in either the first week or second so no conclusions are drawn here on those. Those states are Missouri, Nevada, New Hampshire, Montana and Indiana. Here are states that show movement, some quite strongly, toward Obama:

*Only one poll in this period/state

Except where noted, the before and after numbers are averages of 2 or more polls. You can see that the western states of Colorado and New Mexico appear to be moving strongly towards Obama. Caution is certainly warranted in the Colorado case as we have only 1 post-Sept. 15 poll so far.

Ohio and Virginia both shows compelling shifts toward Obama as well. The other states are moving in the same direction, which confirms the general pattern, but the movements are smaller. Obviously the margins are still very small in some of these locations. Update: This was written before this poll which only adds confirmation to this pattern.

North Dakota (not in the table) seems firmly out of reach based on one poll done during the "McPeak" which showed Obama trailing by 14 and two more recent polls showing Obama behind by an average of 11. The trend (towards Obama) is the same but the margins are so wide it would be tough to overcome in 40+ days.

Summary: state polls are beginning to show the same thing we are seeing in the national polls, a consistent and significant shift toward Obama. The Sept. 15-21 period is not entirely filled in yet as polls to be released over the next several days will have data collection in that period. My own expectation is that those polls will look more like the ones in the right hand column of the table than the middle.