[Editor's note: This post is the first on Pollster.com from our partner Professor Charles Franklin. Charles also blogs at Political Arithmetik, but will also be a regular contributor here. We will be changing the menus and titles next week to designate his contributions approrpriately, but the authors name always appears at the bottom of each post].
Approval of President Bush's handling of his job has taken a significant turn up since mid-August. In ten polls completed since September 1, approval has averaged 39.9%, while disapproval has averaged 55.7%.
Approval around 40% is not particularly good news for any President, but this represents a considerable improvement since earlier in the year.
The chart here plots each of 336 national polls taken since January 1, 2005 that asked a presidential job approval question. The dots represent the poll's approval rate. There is a good deal of scatter in these points, representing the variation due to sampling error, questionnaire effects, survey organization practices, interviewer variability and everything else that causes surveys to vary. While the individual polls vary quite a bit, the trend in approval over the last 21 months is clear. The blue line estimates the trend in approval, allowing each poll to have its say, but keeping to the middle of the range of polls at any point in time, so that the average deviation around the trend line is zero-- the polls above cancel the polls below the trend.
After starting the second term at 50.5% approval, the President's standing with the public declined steadily until November 2005, when it rallied briefly before again sinking to an all time low in May 2006. Following the President's television address on immigration on May 15, however, approval again rallied. The summer produced a steady plateau of approval, but starting around August 15, the trend has once more moved up. The total movement since May has erased most of the ground lost since January 2006, though approval still remains some 10 points below where it stood at the beginning of the second term.
As of polling completed September 14, the trend estimate of approval stands at 40.3%, slightly above the average of the most recent 10 polls. Most of the summer was spent around 37%, so the current standing is a gain of a little over 3 points in a month. The all time low came on May 12 when the approval trend hit 33.98%.
Notice that around that time, polls ranged from a low of 29% to a high of 38%, a good example of how much variation there is across surveys. If one wished to make the President's improvement seem large, one could compare the all time low of 29% with the current highest reading of 43% and conclude there has been a 14 point run-up in approval. If, conversely one wished to minimize the improvement, one might compare the high in mid-may of 38% with the lowest recent reading of 37% and conclude that in fact there has been a one point decline in approval. Both of those comparisons are misleading, of course. The virtue of focusing on the trend estimate is that it is not so sensitive to any single poll, nor to a choice of which poll to compare to which. Based on the trend, the President's approval has risen 6.3% since May 12. Or put in a different way, approval fell by 16.5 points from January 2005 through May 12, 2006. Since then, over six of those points have been regained. This leaves the President 10.2 points below where he started the second term, but with a strong upward trend over the past 4 months.
The interesting question is whether this trend will continue, accelerate, flatten or turn down over the next 53 days until the election, and how much the President's approval rating will affect the vote.