Tuesday, June 13, 2006
SurveyUSA finds approval up to 37%
SurveyUSA's 50 state tracker for June is now out. They find an increase in approval from May to June in 42 of the 50 states, with a national estimate rising from 33% in early May to 37% as of the polls taken 6/9-11/06, following the death of Zarqawi. Despite the move up in approval, President Bush's approval ratings remain below 50% in 45 of the 50 states.
Median approval (the horizontal line inside the red box in the figure above) rose from 35% in May to 37.5% in June, the first upturn since January. The median state approval now matches the values of April and March, but remain well below the median of 43% from January or the high of 45% in June and July of 2005. SurveyUSA's 50 state tracking polls began in May 2005, so no earlier data are available.
The shift from May to June approval was essentially uniform across most states. The blue local regression line is essentially parallel to the 45-degree line for about 43 states. This shows that for these states, the expected gain in approval was the same, with some random variation. For the seven states with the highest May approval, gains were smaller, with the blue line for expected gain approaching the 45-degree line in the upper right portion of the data. Over all states, the median gain was 3.0% (mean was 2.94%). For the 43 states with approval below 45% in May, the median gain was 4% (mean 3.47%) while for the 7 states above 45% in May the median gain was just 1% (mean was -0.29%).
If we compare June to January, we see that the decline in support in the first half of 2006 has been roughly uniform as well. The blue line is not perfectly parallel to the 45-degree line, but it is close enough, and straight enough, that I think the big picture here is that support declined by close the same exptected amount. The median decline was -5% (mean -4.54%).
This pattern of roughly uniform shifts in approval across the states is interesting. It implies that both "red" and "blue" states are about equally affected by the President's shifting performance levels. While a more refined statistical model might pick out some differences, the overall qualitative impression of the changes is that all states shift by about the same average amount from month to month.
To see this, try the animated graphic linked to here. (I couldn't get Blogger to provide a very good image of it, so decided to let dedicated readers who get this far just link to the full resolution version. If the resolution doesn't look good try clicking again on the image to enlarge it to full resolution.) This animation shows approval in each month since June 2005 plotted against the initial May 2005 approval level. The striking thing is that the blue local regression remains pretty much parallel to the 45 degree line across all months, despite considerable shifts in the level of approval over time. Again, there are some minor variations in that story, but overall the striking thing is that there is no "loyal core" that remains high, nor a group of "Bush haters" who are always very negative. Rather it looks like a strong case of uniform national swings in approval. The animation makes clear the small rise in June and July 2005 followed by the substantial declines through November, then a rise back to near May 2005 levels through January 2006 followed by a hard decline through the spring. Whether June marks the beginning of a new upturn, comparable to November-January, or not, remains to be seen. The suspense makes getting up in the morning worth while!
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Regular readers will know that I remain undecided on the automated interviews conducted by SurveyUSA. On the positive side, they begin with a perfectly good random sample of phone numbers, which is far better (I think) than using a non-random group of volunteers for internet based polling. On the other hand, the response rate is quite low so that initial nice random sample now depends on the characteristics of the non-respondents, a huge majority of the original sample. SurveyUSA rightly points out that conventional telephone samples suffer from quite bad response rates too, though not quite as low as the automated systems. SurveyUSA has been unusally open and willing to discuss these matters in professional presentations and on their web site, which I think is a huge plus. But no matter what the technology, high non-response is a threat to any probability sample. So far, the results look pretty well in line with other data and with election outcomes. If the decision to respond is independent of the responses to items (such as approval) then we can get away with low response rates. But if such a correlation should develop, the results will be biased. That is the concern with automated surveys especially because of their low response rates, but it is not irrelevant to conventional telephone surveys with live interviewers either. So I'll use these, and sincerely thank SurveyUSA for making these data available on their site for all to see. But some caution is still needed.
The sponsors of the SurveyUSA 50 state tracking poll are:
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