Little Change in September

Interpreting Polls Legacy blog posts The 2004 Race

Virtually every national survey organization following the presidential race released new surveys in the last four days. Is there any sign of a change during September?

The rolling averages on RealClearPolitics have not changed much, but as they simply average whatever surveys report in a given week, their averages are not always strictly comparable. So I did some of my own calculations this evening.

Seven of the polling organizations that released surveys this week – Gallup, ABC/Washington Post, Time, Fox/Opinion Dynamics, AP/IPSOS, CBS and Zogby – also conducted surveys in the week just after the Republican convention. Using the results available on the Polling Report, I calculated two overall averages of for early and late September, one for “likely voter” samples and another for all registered voters.

In the likely voter samples, Bush led 50% to 43%. His margin is now slightly lower, 49% to 44%, but the differences are not significant even assuming a large pooled sample (note these averages exclude the CBS survey which did not release results for “likely voters”). .

The samples of registered voters looked about the same: Bush led 50% to 43% in early September; he leads 50% to 42% now (Zogby and Fox do not report results for all registered voters).

All but Zogby ask about Bush’s job rating using a scale of approve or disapprove. The average of the six polls in early August (52% approve, 42% disapprove) has not changed significantly (now 52% approve, 43% disapprove).

Thus, once we pool the samples to minimize the effects of sampling error, the vote and presidential job rating have shown little change in September

I will try to explain why in more depth later in the week, but the two numbers I watch most closely are Bush’s job rating and percentage of the vote, as I believe these are most indicative of his ultimate support. That both are hovering just at or above 50 suggest an ultimately close contest, with Bush receiving just about the support he needs to win. The debates will be pivotal.

Mark Blumenthal

Mark Blumenthal is political pollster with deep and varied experience across survey research, campaigns, and media. The original "Mystery Pollster" and co-creator of Pollster.com, he explains complex concepts to a multitude of audiences and how data informs politics and decision-making. A researcher and consultant who crafts effective questions and identifies innovative solutions to deliver results. An award winning political journalist who brings insights and crafts compelling narratives from chaotic data.