A new survey shows Democrat Tom Wolf leading Gov. Tom Corbett by a clear but somewhat smaller margin than in previous post-primary polls.
The poll, conducted for CBS and the New York Times by the Internet polling firm YouGov, shows Mr. Wolf leading the incumbent, 52 percent to 39 percent, including respondents who said they were leaning toward one candidate or the other.
That’s a reasonably comfortable advantage for the Democrat, but well short of the margins of about 20 points he recorded in some earlier polls. Without the leaners, Mr. Wolf’s lead fell to single digits, 42 percent to 33 percent.
The results come after weeks in which both sides have increased the level of attacks on each other through television advertisements and other media.
The survey rests on an innovative and still controversial technique that contrasts with the more traditional methodology of phone polls.
Its responses come from a large panel of registered voters contacted through the Internet. Their responses are then weighted to reflect the demographic characteristics of the entire voting population.
To varying degrees, traditional phone polls also weight their findings to more accurately reflect voting demographics, but they start with samples in which, in theory, every voter has an equal chance of being contacted.
Although some traditional pollsters question the Internet methodology, YouGov has an established track record. Nate Silver, who heads the statistical website 538, rated it with the more accurate performers among all polling firms after each of the last two election cycles.
YouGov has polled for a variety of established media outlets, including the Economist, but this is the first time the high-profile and highly regarded CBS/NYT polling operation has commissioned an Internet survey.
Its panel includes some 100,000 registered voters nationwide who will be interviewed four times between now and November.
The Pennsylvania governor’s results were based on the responses of 4,150 voters.
With leaners included, Mr. Wolf led in most of the demographic subsets of the sample.
With leaners, Mr. Corbett led only among Republicans and conservatives, but he tied his challenger among male voters, whites and independents. Considering only the firmer supporters — without the leaners — Mr. Corbett was ahead among males and independents.
Across the age spectrum, the Democrat’s lead was greatest with younger voters. He led 61 percent to 23 percent among voters age 18 to 29, and 55 percent to 32 percent with voters between 30 and 44.
But the results were significantly closer with the older voters who are most likely to turn up at the polls — 50 percent to 46 percent in favor of Mr. Wolf with those 45 to 64 and 50 percent to 47 percent among those over 65.
The results suggest that Mr. Wolf has done a better job consolidating his party base. He led 90 percent to 5 percent among Democrats while Mr. Corbett’s GOP advantage was 80 percent to 16 percent.
James P. O'Toole: email@example.com or 412-263-1562.