These two websites provide information on the approval ratings of George W. Bush over time. Data come from a number of different polls that regularly include a question about approval of the President of the United States.
Data shown in a
graph:
Pollkatz Graph
Data from several polls shown as raw numbers:
http://www.pollingreport.com/BushJob.htm
The data can be used in several ways to illustrate aspects of survey sampling, replications, and the impact of 9/11 on the approval ratings.
What follows is a post about these data on the Society for Personality and Social Psychology e-mail discussion forum from Dr. Alan Reifman. Dr. Reifman's comments apply primarily to the graphical version of Bush's approval ratings, rather than the raw-numbers version. Thanks to Dr. Reifman for allowing this to be printed here.
The website plots George W. Bush's approval rating over time, with separate data points for each major media polling agency (media outfits can be identified by color-coded shapes). I think we probably all advise our students not to look at any one research finding, but rather to see what several replications yield. The website provides exactly this information, as for any given week (or so), several agencies will have polled. As you'll see from the web page, at any one given time, the pollsters will be in general agreement (e.g., right after 9-11, most polls found bush's approval rating between 80-90%), but there's always some range.
Besides the aforementioned topic of replication, this chart can be used to facilitate discussion of how scientifically done polls should converge on the population parameter for a given time point (how literally all Americans would respond if surveyed). Yet, because of random sampling error (and the associated margin of error to be attached to any sample's finding) and systematic differences between polling agencies (how they word the question, how they obtain their list of phone numbers, how they weight the sample, etc.), there will be that range of approval ratings at any one time. In terms of poll differences that appear to be relatively systematic, you'll notice that the Investor's Business Daily/Christian Science Monitor (IBD/CSM) poll (the little orange circles) tends consistently to register the lowest Bush approval ratings, whereas the ABC-Washington Post poll (the little blue diamonds) tends to give Bush high ratings.
The chart could also be used to illustrate interrupted time-series analysis, with 9-11 being the intervening event. I think we're all familiar with the aphorism "A picture is worth a thousand words." In my opinion, this one chart really gets across the concepts of replication and survey variability about as powerfully and concisely as anything I could imagine.
An excellent discussion of sources of error in polling can be accessed at: http://www.pollingreport.com/sampling.htmAlan Reifman, Ph. D.,
Assistant Professor Dept of Human Dev't and Family Studies
College of Human Sciences
Texas Tech University
Lubbock, TX 79409-1162
http://www.hs.ttu.edu/hdfs/Faculty/reifman.htm
An interesting influence on responses is the nature of the other questions in the survey. If you look at the graph of the approval ratings, you will see that the data from the American Research Group shows consistently lower approval than most others. This organization conducts regular polls of the national economy with questions that focus on perceptions of the state of the economy and current and anticipated future personal finances. It may be that making the issue of the economy salient lowers the approval of the president.
Here are some of the questions used by the polling organizations to measure approval:
Gallup Poll and CNN/USA Today/Gallup Poll
CBS News and The New York Times
Pew Research Center for the People & the Press
Newsweek
ABC News and The Washington Post
American Research Group
"Do you approve or disapprove of the way George W. Bush is handling his job as president?"
Zogby International America Poll and Reuters/Zogby Poll
President Bush -- Job Rating: Excellent/Good, Fair/Poor or Not Sure
FOX News/Opinion Dynamics Poll
"Do you approve or disapprove of the job George W. Bush is doing as president?"
The Harris Poll
"How would you rate the overall job President George W. Bush is doing as president: excellent, pretty good, only fair, or poor?"
NBC News/Wall Street Journal Poll
"In general, do you approve or disapprove of the job George W. Bush is doing as president?"
CNN/Time Poll
"In general, do you approve or disapprove of the way President Bush is handling his job as president?"
