Gap in Pa. Senate Race Likely Bigger Than Reported
10:29 AM, Oct 22, 2010 • By JEFFREY H. ANDERSON
Many people are talking about the dramatic tightening of the Pennsylvania Senate race between Republican Pat Toomey and Democrat Joe Sestak. But upon closer inspection, most of that apparent tightening seems to be a mirage.
The sense that Toomey's lead has substantially narrowed is based on three polls: one by PPP, which shows Sestak up 1; one by Quinnipiac, which shows Toomey up 2; and one by Morning Call Tracking, which shows a tie. These are the only polls that have been released since Rasmussen showed Toomey to be up 10 points just a week ago. However, all three polls appear to have significantly under-sampled the very voters who will likely put Toomey over the top.
John McCormack has written about the PPP poll (which Real Clear Politics designates as a Democratic poll). That poll's likely voter sample includes an even wider gap between Democrats and Republicans (+7 Democratic) than the gap measured by exit polls during the last midterm elections (+5 Democratic) -- when Democrats picked up 31 seats in the House. The odds of the Democrats securing a better turnout in 2010 than in 2006 are about the same as the odds that President Obama will admit that ObamaCare was a colossal mistake and needs to be repealed.
Unlike PPP, the Quinnipiac poll doesn't indicate how many of its respondents are Democrats, Republicans, or independents. But it does show what percentage of each group is supporting each candidate. Based on those percentages (Democrats favor Sestak 89 to 7 percent, Republicans favor Toomey 88 to 8 percent, and independents favor Toomey 56 to 35 percent), if the split in turnout were the same as in 2004 (41 percent Democrats, 39 percent Republicans, 20 percent independents), Toomey would win by 2 points. And that's what the survey shows: Toomey by 2. So whatever its exact breakdown of respondents by party, this survey is predicting essentially the same party turnout as that which materialized in 2004, a year in which neither party had a clear edge in voter enthusiasm.
That isn't the case this time around.
If, therefore, in comparison to 2004, we conservatively assume a 3-point decrease in the percentage of voters who are Democrats (to 38 percent), a 2-point increase in the percentage who are Republicans (to 41 percent), and a 1 point increase in the percentage who are independents (to 21 percent), this poll's results would instead show Toomey with a 6-point edge: 50.5 percent to 44.5 percent.
In fact, if anything the Quinnipiac poll shows Toomey's numbers looking slightly better than they did in the previous Quinnipiac poll, from a month ago, when he was said to have a 7-point lead. Since then, Toomey has gained 2 points of support among Republicans (from 86 to 88 percent), 2 points among independents (from 54 to 56 percent), and hasn't lost any ground among Democrats (7 percent). Meanwhile, Sestak has gained 2 points among Democrats but has lost a point among Republicans and another point among independents. This means that Toomey's alleged decline from a 7-point to a 2-point lead can only be attributed to Quinnipiac's having included a greater percentage of Democrats in its polling sample this time around.