Obama Landslide, or Nailbiter?

Trying to follow the polls during this election season can make one dizzy. Are we headed for an Obama landslide and a 10- or 11-percent margin of victory? Or is this race still close, with Obama ahead by about 5 percent? The answer depends not only on which polls you read, but — I would argue — on how those polls are reported, especially with regard to the partisan breakdown of survey sample and the seeming dearth of undecided voters.

PARTISAN BREAKDOWN

Let me start with the Obama landslide polls — the most recent examples being a Newsweek poll released on October 11 showing an 11-point lead for Senator Obama and an ABC News/Washington Post Poll released on October 12 showing a similar 10-point lead. No doubt such polls cause great concern among McCain supporters — but should they? As with all polls, the best data comes from what we political diehards call “the internals” or the results below the line that measure candidate support among key demographic groups or public support for candidates on certain issues (the economy, the war, etc). 

Consider the Newsweek poll. Although the poll reports that Obama leads McCain 52 percent to 41 percent overall, the poll also shows that McCain is winning Independent voters 45 percent to 43 percent. Obama is winning Democrats 91 percent to 5 percent and McCain wins Republican by 89 percent to 7 percent. From these numbers, it’s difficult to understand Obama’s 11-point advantage — until you look further into the polls internals and see that the results are based on a respondent sample that was 40 percent Democrat (D), 27 percent Republican (R), and 30 percent Independent (I). Three percent expressed no preference. To see how that affects overall support one need only multiply each candidate’s level of partisan support (D, R, or I) by each group’s percentage of the overall sample. As shown in the table below, Obama’s 52 percent is based on 91 percent support among Democrats multiplied by Democrats 40 percent proportion in the poll, his 7 percent support among Republicans (27 percent of the respondents) and his 43 percent support among Independents (33 percent of respondents — add the “no preference” folks to this group). Tally Obama’s support across the three groups and you arrive at 52 percent. If you follow the same calculations for McCain, you’ll arrive at 41 percent. 

The problem is: In no recent election has the Democratic Party (or any party) enjoyed such an advantage among the American electorate. In 2004, exit polling data found the electorate to be 37 percent D, 37 percent R and 26 percent I. In the 2006 midterm elections for the House of Representatives the electorate was 38 percent D, 36 percent R, and 26 percent I. In 1996 and 2000, Democrats enjoyed a 4-point edge over Republicans. Given this history, it seems hard to believe that the Democrats have suddenly leapt to a 13-point partisan advantage. If one takes the Newsweek results and re-weights them to reflect a more realistic 4 point partisan advantage for Democrats the results change significantly. As can be seen in the following table, Obama’s 11-point lead shrinks to 4.

If one were to assume that partisan turnout in 2008 is the same as 2006 (38 percent D, 36 percent R and 26 percent I) then Obama’s lead would drop to 2 percent. But turnout in 2008 is likely to favor Democrats, leading me to believe that Obama has a lead in the neighborhood of 4 to 5 percent. The ABC News/Washington Post poll reported a 9-percent partisan advantage for Democrats and, similar to Newsweek, reported a significant Obama advantage. 

Recent polls by Zogby and Rasmussen show Obama with a 4- to 5-point lead. Unlike Newsweek, Zogby and Rasmussen weight their samples to reflect what they consider to be the likely partisan makeup of the American electorate and are finding a closer contest in their polls. Interestingly, Rasmussen is assuming a 6-percent partisan advantage for Democrats.

WHERE HAVE ALL THE UNDECIDEDS GONE?

The other issue to consider when looking at polling data is the number of undecided voters. Most polls are showing remarkably few undecided voters. Newsweek reports 6 percent undecided, ABC News finds only 2 percent. Rasmussen reports none. Yet Zogby finds 8 percent undecided and a recent FoxNews poll found nearly 15 percent of the electorate to be undecided. How can this be?

The answer is that most polls “force” undecided respondents to name a preference for a candidate. These “leaners” as they are often called are then lumped in with everyone else as if they were committed supporters. This approach is misleading. According the American National Election Study (which has been examining the American electorate since 1948), in every presidential election since 1992, 15 to 20 percent of the electorate did not make up their mind until the final two weeks before Election Day. Asking respondents to “lean” one way or the other when they are truly undecided creates the false impression that a trailing candidate has very few voters left to convince. In the ABC News poll, 15 percent of Senator McCain’s supporters and 12 percent of Senator Obama’s indicated that the could change their mind before Election Day. If the behavior of the electorate in past elections is any indication, then the final few weeks of the 2008 campaign should provide ample opportunity for movement in this race.

In the end, the polling data suggests that John McCain trails Barack Obama by 4 to 5 percent. Although Obama has enjoyed that lead rather consistently since recent events have catapulted the economy to the top of most voter’s concerns, a 4- to 5-percent lead is far from insurmountable — and the closing weeks of an election is the very time when as many as one in five voters are tuning in and deciding which candidate to support.

– Todd Eberly is an assistant professor of political science at St. Mary’s College of Maryland.