No trends found for Ohio, just a two-point debate effect.
I usually do not publish raw regression results on the main pages of this blog, relegating them instead to the Technical Topics category. However rather than spend time building an uninformative graph of the Ohio campaign, I’ll just report the results here and explain their meaning.
I have applied the simple trends and house effects model that I developed for national polling to the results for Ohio. Once again I am using the Pollster archive and including all polls of “likely” voters conducted after June 30th. I also included a variable for the first Presidential debate and dummies for the pollsters to measure house effects. I get these results:
Model 15: OLS, using observations 1-66 Dependent variable: Dem_Lead coefficient std. error t-ratio p-value ------------------------------------------------------------ const 5.31164 1.00663 5.277 2.21e-06 *** DaysBefore −0.0235519 0.0147563 −1.596 0.1161 Debate1 −2.23855 0.845398 −2.648 0.0105 ** Rasmussen −2.65019 0.821597 −3.226 0.0021 *** Gravis Mktg −2.28954 0.925727 −2.473 0.0164 ** ARG −2.39894 1.26821 −1.892 0.0637 * NBC/WSJ/Marist 3.37662 1.27493 2.648 0.0105 ** Wenzel/CtznsU −5.55798 2.20545 −2.520 0.0146 ** Qunn/NYT/CBS 3.74099 1.31111 2.853 0.0061 *** WaPo 3.72465 2.17768 1.710 0.0927 * Mean dependent var 2.939394 S.D. dependent var 2.833203 Sum squared resid 250.9900 S.E. of regression 2.117065 R-squared 0.518953 Adjusted R-squared 0.441642 F(9, 56) 6.712523 P-value(F) 1.86e-06
First, we see at best only a very weak trend in the President’s favor over the course of the summer, one that fails to prove significant even at the 0.10 level. The best interpretation is that there have been no discernible trends in Ohio since June, just a one-time drop of two points in the President’s lead from a bit over five percent before the first Presidential debate to three since then.
Seven pollsters showed statistically significant deviations from the consensus for Ohio though only Rasmussen and ARG also appeared on the list for national polls. The measured effects for those two organizations in Ohio are both slightly larger than the effects measured in national polling.
Polls by the three major media organizations — NBC/WSJ/Marist, Quinnipiac/NY Times/CBS, and the Washington Post — all had results over three points more Democratic than the consensus. While these organizations are often criticized as being “in the tank” for Obama (leaving aside the Wall Street Journal, of course), I don’t find any such partisan bias in their national polling. The poll with the largest outlier, Wenzel/Citizens United, had a obvious partisan sponsor and reported results consistent with its Republican ideology.
