Spetember 13, 2004
Why the Race Is Closer Than People Think
Is Bush ahead by a little or a lot? Is it close to a tie ball game or has Bush surged to a commanding lead?
The conventional wisdom inclines to the latter not the former. The reason has a great deal to do with two persistent problems with contemporary polls that--at least at this point in time--tend to considerably inflate Bush's apparent lead. But once you dissect the available data with these problems in mind, a truer picture of the race comes into focus which suggests that the race continues to be very close.
The two problems are: (1) samples that have an unrealistic number of Republican identifiers and hence tend to favor Bush; and (2) the widespread and highly questionable practice of using likely voters (LVs) instead of registered voters (RVs) to measure voter sentiment this far before the election.
First, the issue of partisan distribution in samples. Lately, and very suddenly, many polls have been turning up more Republican identifiers than Democratic identifiers in their samples--in some cases, many more (as high as a 9-10 point Republican advantage).
How realistic is it to be suddenly turning up a Republican lead on party ID, much less a large one? Not very. The weight of the academic evidence is that, while the distribution of party ID among voters can and does change over time, it changes slowly, not in big lurches from week to week.
And the weight of the empirical evidence is that the distribution of party ID among voters has favored and continues to favor the Democrats. In 2000, the exit polls showed Democrats with a 4 point advantage over Republicans. In 1996, it was also 5 points; in 1996, it was 3 points and in 1988 it was also 3 points.
The data also indicate that there were two shifts in party ID over the 2001-04 period which largely cancelled each other out. The first shift, in the period after 9/11, shaved several points off the Democrats' lead and brought the Republicans close to even (but never ahead) in party ID. The second shift tooks place in late 2003 and 2004 and reconstituted the Democrats' lead on party ID to about 4 points, exactly where it was in the 2000 election according to the exit polls (see this useful study "Democrats Gain Edge in Party Identification" by the Pew Research Center for more details). ...
The other problem that is afflicting the polls and considerably inflating perceptions of Bush's lead is the widespread, and highly questionable, use of LVs, instead of RVs, to report horse race results far in advance of the actual election. The reason why using LVs instead of RVs is a bad idea is simple: the LV approach is being asked to do a job--gauge voter sentiment and how it changes from week-to-week (and even day-to-day)--that it was never designed to do. What the LV approach was designed to do was measure voter sentiment on the eve of an election and predict the outcome. That was, and remains, an appropriate application of the LV approach.
But applied as many polling organizations currently do, it is highly inappropriate and frequently very misleading. As political scientists Robert Erikson, Costas Panagopoulos and Christopher Wlezien put in in their important forthcoming paper, "Likely (and Unlikely) Voters and the Assessment of Campaign Dynamics" in Public Opinion Quarterly:
'[E]stimates of who may be likely voters in the weeks and months prior to Election Day in large part reflect transient political interest on the day of the poll, which might have little bearing on voter interests on the day of the election. Likely voters early in the campaign do not necessarily represent likely voters on Election Day. Early likely voter samples might well represent the pool of potential voters sufficiently excited to vote if a snap election were to be called on the day of the poll. But these are not necessarily the same people motivated to vote on Election Day.'
And of course, since the group of people "sufficiently excited to vote if a snap election were to be called on the day of the poll" changes from poll to poll, it raises the uncomfortable possibility that observed changes in the sentiments of "likely voters" represent not actual changes in voter sentiment, but rather changes in the composition of likely voter samples as political enthusiasm waxes and wanes among the different parties' supporters.
Or, as Erikson et. al. put it:
'At one time, Democratic voters may be excited and therefore appear more likely to vote than usual. The next period the Republicans may appear more excited and eager to vote. As Gallup’s likely voter screen absorbs these signals of partisan energy, the party with the surging interest gains in the likely-voter vote. As compensation, the party with sagging interest must decline in the likely-voter totals.'
And this is exactly what their analysis of Gallup data from the 2000 election finds--"shifts in voter classification as likely or unlikely account for more observed change in the preferences of likely voters than do actual changes in voters’ candidate preferences".
This is an important result and helps nail down what has always been disturbing about the use of likely voter methods far in advance of the actual election. Instead of giving you a better picture of voter sentiment and how it is changing than conventional RV data, it gives you a worse one since true changes in voter sentiment are swamped by changes in who is classified as a likely voter.
In short, these LV figures, especially from Gallup, are contributing mightily to the impression that Bush has built a substantial lead and is even surging ahead in some of the key swing states. But, as we have seen, these LV data are fundamentally inappropriate for measuring the state of the race, and how it is changing, this far ahead of election day. For that, you need the RV data and they suggest something far different: the race is damn close and Bush's substantial lead is a myth.
Copyright © 2003-2004 by Ruy Teixeira