If you have already glanced at our front page today, you know that we have introduced three new charts using the same Flash software that displayed pre-election polling results last year. All three are based on results from national surveys and are accompanied by tables that include links to the underlying source data:
- Barack Obama's favorable rating - displays results back as far as January 2007, when most national polling organizations first started asking Americans to rate him.
- Obama's job approval rating - currently based on questions about how Obama is handling "his presidential transition," this chart will evolve into one that tracks questions about how he handles his "job as president" once pollsters switch to that language after inauguration day.
- Right direction, wrong track - tracks answers to the question, "do you think things in this country are generally going in the right direction or are they seriously off on the wrong track," as asked by a dozen or so pollsters since Labor Day, 2008. Later this year, we hope to add more data going back further in time
These three are just the beginning. We are also planning to add many more national measures over the course of the next few months, and of course, for election tracking graphs for 2009 and 2010 races as data becomes available. Our menus and sidebar links should update within the next few days to allow easier navigation to the new charts.
Again, the charts use the same Flash display software that we used during the fall campaign (static non-Flash graphic versions are displayed for those without a Flash capable browser). Pointing your mouse to any individual data point on the chart will pop-up information about that poll (pollster, survey dates, sample size, etc.). Clicking on that point will connect-the-dots to other results from the same organization. Options accessed through the tools menu allow you to filter out polls by any organization or by the mode of the survey, vary the sensitivity of the trend line, change the axis ranges and embed your chart, customized as you prefer, on your own blog or web page. We produced a video back in September that demonstrates most of these features.
One thing you will notice immediately is that some of these charts show more distinct "house effects" than the horse race results we typically plot. The favorable rating in particular shows big differences, owing to the sometimes very different ways that pollsters ask Americans to rate their general impressions of political leaders. Notice, for example, the way the Rasmussen surveys produce a greater unfavorable percentage for Obama and the way the CBS/New York Times wording produces lower percentages for both the favorable and unfavorable categories. I wrote about some of these differences, particularly as they affect the CBS/New York Times results, in a column back in July, along with a sidebar post that included the text of the favorable rating question asked by each national pollster.
By playing with the "filter" feature in the charts, you can get a sense for the degree to which removing any pollster or combinations of pollsters affect our overall estimate. What you will find is that the loess regression line is mostly resistant to minor "house effects," even major ones. Remove the frequently updating Rasmussen automated tracking, for example, and the overall estimate changes from 71.5%-17.8% (favorable-unfavorable) with all polls included to 72.5%-16.0% without.