Supplement to Dreaminonempty's Approval Diaries
Work in progress. Coming soon: district and county level approval. The intent of this page is to put archives of old approval maps on here, as well as explanations of how estimates are done, and other things that can assist the occasional diary series.
In order to estimate Bush’s approval in geographic areas where no polls are available, regressions are used. For example, for the maps of approval by state, Survey USA stopped polling every state in November 2006, and cut back to about 15 states. These polling results are combined and averaged with all other statewide polling data available on Bush’s approval rating, and plotted against the average Survey USA approval rating for the period August-October 2006. From this, a regression line and an equation that describes this line are generated. This equation can then be used to estimate the approval ratings in states where no polls were taken that month, typically with a 95% confidence interval of 5-6 percentage points. This means that if we estimate an approval of, say, 30% in Illinois, we can be pretty sure that the true approval lies between 25 and 35%. Note that the Survey USA polls themselves have a 95% confidence interval (or margin of error) of 4 percentage points.
The Use of Color
Ideally, maps of this sort should not use both red and blue. However, the convention of red states and blue states, with purple states in between, is well-established after the 2000 election. On either the red or blue side of the maps, darker colors correspond to more extreme values. In order to allow the viewer to differentiate colors, the difference from one level to another was so large that the far extremes of approval had to move into green (on the disapproval side) and purple (on the approval side).
One could argue that shades of red only should be used, as the maps show only approval of Bush, and disapproval of Bush is not equivalent to having a positive view towards Democrats. The use of blue and green shades on the map could therefore be considered misleading. On the other hand, disapproval of Bush is much more than simply the absence of approval. Also, in politics, the 50% level matters, and we like to be able to easily tell the difference between values greater or less than 50%. Neither way is perfect, but use of both blue and red allows for easier differentiation between levels of support. Finally, the 2006 election showed that Bush’s approval did indeed have a substantial relationship to the support for Democrats at the House level, which means the use of blue on the maps is not as misleading as one might otherwise think.
County and District Approval Archives
State Approval Archives
Also available as an animation.