That Rumored Hispanic Revision?

Exit Polls Legacy blog posts

It’s now apparently official.  Brosnan of the Scripps Howard News Service reports and includes a hint as to how the "revision" was accomplished:

Initial network exit polls on Election Day overestimated President Bush’s support among Hispanic voters, an NBC official said Thursday.

Revised figures show Bush received 40 percent of the Hispanic vote, not 44 percent, said Ana Maria Arumi, elections managers for NBC News. That would still be a 5-percentage point gain for Bush over Democrat John Kerry compared to the 2000 race against Al Gore…

The major television networks used pollster Warren Mitofsky to sample 250 key precincts on Election Day. Arumi said the exit poll over sampled in South Florida where Republicans are strong among Cuban-Americans.

For the revised figures the networks combined 50 state exit polls, which reflected more than 70,000 interviews, Arumi said.

To clarify (what I can) from the above:

The National Election Poll (NEP) sampled far more than 250 precincts on Election Day.  That may have been a reference to the number of predominantly Latino precincts.   I also assume that the reference to "oversampling" of Cuban voters in South Florida was something NEP did intentionally, and then weighted back appropriately in the previously released Florida results.  This would have been a strategy to counteract the problem I described on Wednesday and assure an adequate and more accurate sampling of Florida’s Cuban voters [Perhaps not — see below]

The last quoted paragraph is also important:  On Election Day, the National Election Pool (NEP) did a seperate, stand-alone national exit poll of roughly 14,000 interviews that produced the intial estimate of Bush’s support among Hispanics at 44%.  If this report is right, they have subsequently rolled together all of the interviews conducted in the various statewide exit polls (and weighted them so that the full sample is geographically correct.   The larger sampling of Latino precincts would have less sampling error; thus the downward revision.

Still unclear is whether they did 70,000 interviews statewide (the number you get if you add up all the reported sample sizes reported on sites like CNN.com; see this MIT/Cal Tech report) or the roughly 150,000 that Warren Mitofsky reported on the News Hour.   Yet another question for Shuster’s press conference

UPDATE:  Another article on this press conference by Rueters’ Alan Elsner implies that the overrepresentation in Florida was not intentional:

Looking at a larger state-by-state sample of 70,000 voters conducted Election Day, NBC elections manager Ana Maria Arumi said the original exit poll had overrepresented Hispanics in southern Florida, who were more likely to be pro-Bush than Latino voters elsewhere.

"The number now comes out at 58 percent for Kerry and 40 percent for Bush," Arumi said at a news conference.

The William C. Velasquez Institute, the organization that sponsored the forum at which Arumi spoke, also put out a press release with more details.   And not suprisingly, Ruy Teixeira is all over this issue.

UPDATE II:  Blogger Steve Sailor anticipated the rationale for this revision in some interesting thoughts posted the comments section in my earlier post.   

Mark Blumenthal

Mark Blumenthal is political pollster with deep and varied experience across survey research, campaigns, and media. The original "Mystery Pollster" and co-creator of Pollster.com, he explains complex concepts to a multitude of audiences and how data informs politics and decision-making. A researcher and consultant who crafts effective questions and identifies innovative solutions to deliver results. An award winning political journalist who brings insights and crafts compelling narratives from chaotic data.