Mark Blumenthal | March 2, 2008
Topics: 2008 , Barack Obama , Divergent Polls , Hillary Clinton , Likely Voters , SurveyUSA
The Columbus Dispatch released a mail-in survey of registered Democrats and Republicans in Ohio this morning. We have chosen not to include that survey in our chart for the Ohio primary because the Dispatch made the odd choice of sampling only registered Democrats and Republicans in a semi-open primary that allows non-partisan registrants to participate. We did briefly and inadvertently include the poll in our chart earlier this afternoon, but have removed it.
The Columbus Dispatch has long conducted pre-election polls by mail, but our issue with this particular survey is unrelated to its mode. The Dispatch sends out poll "ballots" to voters randomly selected from Ohio's list of registered voters. This method has been surprisingly accurate in general elections since 1980, something I wrote about approvingly in October 2004. On the other hand, the Dispatch poll produced a disastrous result on a set of ballot initiatives in 2005, owing partly to some deviations from their usual methodology, such as not replicating the exact ballot language, including an undecided option and fielding the survey a week earlier than usual.
However, in this case, the key issue is that the Dispatch sampled only registered partisans, that is, voters with some previous history of voting in primaries. Why does that matter?
Ohio has a "semi-open" primary. The state has no formal "party registration," in that voters do not choose a party when they register to vote. However, those who vote in primaries have their party affiliation recorded in the voter lists. Those who have previously voted in a primary and want to switch their party affiliation can do so by filling out a form on primary day (or when they request an absentee ballot). But those who have never voted in a primary before [and are registered to vote] -- those considered "non-partisan" by the registrar of voters -- can opt to participate in any primary simply by showing up on Election Day (for more details, see the blog post by Pollster reader Tom Fox).
As of 2006, Ohio had 7.6 million registered voters, but only 2.4 million voted in the primary election (of either party) in 2004. Slightly more, 2.5 million, voted in the Ohio primary in 2000, and the turnouts in off-year primaries are lower.
As such, the majority of Ohio's registered voters do not participate in primaries and are, therefore, registered as "non-partisan" but yet still fully eligible to participate in Tuesday's primary. The current voter file maintained by Voter Contact Services (a political list vendor) includes 7.9 million registered voters of whom 20% are "registered Democrats," 19% are registered Republicans and 60% are non-affiliated.
Keep in mind that "party registration" in Ohio is very different from the self-reported "party identification" that most surveys measure. While 60% are unaffiliated on the voter lists, a recent SurveyUSA poll of registered voters finds only 23% identifying as "independent" (while 44% identify as Democrats and 29% as Republicans).
Typically, most primary voters in Ohio have voted in primaries before. So the choice by the Dispatch to sample only those with previous primary history may have been appropriate for typical off-year primaries. The 2008 primary will be anything but typical, however, and their decision to exclude non-partisan voters from their sample is questionable.
Ohio's Secretary of State Jennifer Brunner is predicting that 52% of Ohio's registered voters will participate this week, a level that the Associated Press appropriately described as "incredibly high." They also reported that Brunner cited as as evidence the early requests for absentee ballots and the experience of other states this year.
As the Dispatch observed, if Brunner is right and this week's turnout hits 4 million, it would mean that "well more than a quarter of Ohio's 5 million-plus nonpartisan voters will vote" in the primary. That means that roughly 30% percent of the voters in the two primaries would be unaffiliated. Presumably, given the interest in the Obama-Clinton race, the percentage of non-affiliated voters in the Democratic primary would be higher.
Of course, the percentage of unaffiliated voters that turn out on Tuesday is a matter of speculation. However, since the Dispatch sample design entirely excludes this potentially critical category of voters from its sample, we are not including it in our trend chart.