Wednesday, August 23, 2006

Bush Approval: CBS steady at 36%

The new CBS/New York Times poll, conducted 8/17-21/06, finds approval unchanged at 36%, with disapproval also stable at 57%. Those are the same ratings CBS/NYT found in a poll taken 8/11-13, immediately after the British foiled a terrorist plot against U.S. bound aircraft. In CBS/NYT's last poll before the plot was disclosed, approval was 36 with disapproval at 55. That poll was completed 7/21-25. With the latest CBS/NYT data included, my trend estimator for President Bush's job rating now stands at 37.6%, revised down a bit from yesterday's 38% estimate in which the CNN/ORC and USAToday/Gallup polls at 42% approval exerted a substantial influence. If further polling confirms that the CNN and USAT polls are indeed outliers (as I showed in previous posts here and here) then the influence the polls have on the trend will diminish. In terms of the trend estimator, what appeared to be an upward slope yesterday has now returned to a flat trajectory between 37% and 38%.

Basing a conclusion on a single organization's polling is risky, but in this case at least the impact of the plane plot appears to be nil. The reason to use the CBS/NYT data is that they conducted a poll close to, but before, the plot was announced, then one immediately after and now a third poll a week later. Since it is the same organization conducting all three, house effects won't influence change between polls, confounding the impact of the plot. Further, the sample sizes are substantial, so we aren't dealing with a small sample in any of the three surveys.

One doesn't need a lot of statistics to conclude that 36-36-36 represents rather little evidence of change.

There are 5 polling organizations that have good pre-post plot polls we can use to take a broader look at the effect of the terror plot impact:
Pew, 7/6-19 and 8/9-13*
Zogby, 7/21-25 and 8/11-15
Gallup, 7/28-30 & 8/18-20**
CNN, 8/2-3 and 8/18-20
CBS/NYT 7/21-25 & 8/11-13

* Pew's first day of interviewing was before the plot was revieled in the US
** Gallup did a 8/7-10 that included one day after the plot was exposed
(Newsweek has a post plot poll, but their pre-poll is from May, a useless comparison.)

If we compare the post minus pre approvals WITHIN poll, thus removing house effects, we get the following changes from pre to post:
for an average change of +0.8%.

The conclusion is clear. No impact of the plot on presidential approval directly.

The plot may well have increased the salience of terrorism and the sense of threat. We have seen terrorism rise as the "most important problem" in some polls. But so far at least, that has had no discernible effect on presidential approval.

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