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January 26, 2006

Party ID Updates

Here is another quick update on some interesting releases over the last week or so on the subject of party identification from Harris and Gallup.   Two new reports - based on a full year's worth of data - show a slightly greater Democratic advantage in 2005 than 2004, however similar data from the Pew Research Center shows no such trend.

  • Harris Interactive released their annual review of the long term trend in party identification and self-reported ideology.   Their conclusion, based on rolling together data from 4,945 US adults interviewed by telephone during 2005:  36% of Americans identified as Democrats (up from 34% in 2004) and 30% identified as Republicans (down from 31% in 2004).  The six point Democratic edge is "the largest lead since 2000."

The table showing 36 years of data on party identification is well worth the click, and worth comparing to a similar table of party ID results from American National Election Studies conducted in even numbered years since 1952 by the University of Michigan. 

  • Gallup released their own compilation based on their massive pool of 42,431 interviews conducted among US adults during 2005 (and the report appears to be free to all).  The report provides the results to the root party identification question for 2005 only (33% Republican, 33% Democrat).  They provide trended data based on the combined percentage of partisans plus those who initially identify as independents but say the "lean" to one of the parties on a follow-up question. 

Among those who identify or lean to one of the parties, their results also show a growing Democratic advantage in 2005. The Democratic edge increased from a margin of 2.7 percentage points in 2004 (47.9% to 45.2%) to 4.5 points (47.% to 43.2%) in 2005.  Jeff Jones report also provides party identification data for all 50 states. 

  • The Pew Research Center also provides annualized results for party identification on the "topline" questionnaire it releases with every survey, but only for the root party ID question (not for "leaners"). Their results show no change in party identification from 2004 to 2005.  In both years, 33% identified as Democrats, 30% as Republicans.

Keep in mind that the Michigan/Harris version of the party ID question differs slightly from the one used by Gallup.

Michigan and Harris ask:  Generally speaking, do you consider yourself a Republican, a Democrat, an independent or what?

Gallup asks:  In politics, as of today, do you consider yourself a Republican, a Democrat, or an Independent?

As noted here before, although the political scientists continue to debate the issue, some have produced evidence that the Gallup version allows for short term variation.

PS:  Occasional MP commenter DemFromCt has posted thoughts on what all of this might mean for Democrats on the Next Hurrah

Related Entries - Weighting by Party

Posted by Mark Blumenthal on January 26, 2006 at 01:02 PM in Weighting by Party | Permalink


The party numbers just didn't seem right to me so I did some further investigation.

I took the 14 election years covered by the ANES data (1952 to 2004) and compared them to the popular vote totals for the presidential elections in those 14 election years. I was looking for how the popular vote percentage matched up to the ANES party identification percentage. I recognize that there isn’t a one to one match up, but comparing the percentages gives a feel for the issue. If a party is consistently capturing a percentage more or less than those identifying themselves with the party, then you have to ask yourself how accurate is the party identification.

The result was 14 out of 14 times, the republicans got 100% of the strong, weak and independent republicans and at least a portion of the independents. 12 out of 14 times, the portion of independents captured was greater than 85%. The only two times that the republicans captured less than 85% of the independent vote was ’92 and ’94 when the “other party” candidate took more than 10% of the total. 9 out of 14 times, the republicans got 100% of the strong, weak and independent republicans, 100% the independents and a portion of the independent democrats. 3 out of 14 times, the republicans got 100% of the strong, weak and independent republicans, 100% the independents, 100% of the independent democrats and a portion of the weak democrats.

The corollary to this is that the democrats only captured all the strong and weak democrats 10 out of 14 times. They only captured all the strong, weak and independent democrats once out of 14 times (Johnson’s 1964 land slide when 0.006% of the independents also voted for Johnson).

So looking at the last 14 presidential election years, the percentage of people voting democrat has been less than those identifying themselves as some sort of democrat (strong, weak or independent leaner towards democrats) in the ANES polls 93% of the time. While the percentage of people in the last 14 presidential election years who voted republican have always been more than those calling themselves some sort of republican (strong, weak or independent) in the ANES polls. In fact, 9 of the 14 times, it would seem that 100% of the independents were also republicans. 12 of the 14 times, it would seem that more than 85% of the independents were also republicans. So the ANES has 13 of the last 14 presidential election years over counted democrats (and the one time they didn’t over count, they were only under by 0.05%), 14 out of 14 times undercounted republicans and 9 out of 14 times all those claiming to be independent independents were really republicans (or at least people who voted for the party).

So what to make of this? It would seem that for the terms democrat, independent and republican, in the words of Inigo Montoya “You keep using that word. I do not think it means what you think it means.” People are consistently calling themselves democrat, but that percentage is not being reflected in the presidential election percentages. 86% of the time, independents are overwhelmingly supporting republicans (and the only exceptions was when there was a strong independent challenge).

Maybe it’s the libertarian minded people who are calling themselves true independents or independent democrats, but are consistently siding with the republicans. Whatever the case, when the polls are this far off in matching party identification in the polls to presidential election year voting, then how much faith can you put in polls that never have a real world check on their accuracy like we do with the presidential elections.

Posted by: yetanotherjohn | Jan 27, 2006 7:02:06 PM

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