BROWN v. COAKLEY: LIES, DAMNED LIES, and STATISTICS

January 11, 2010

UPDATE FRIDAY, 01.14.10: A just issued Suffolk University poll now puts MA State Senator Scott Brown at 50% v. 47% for MA AG Martha Coakley in their bid to become the next U.S. Senator from the Bay State. The margin of error is + or – 4.38%. http://www.suffolk.edu/39994.html (Note: check out the cross tabs. You will see, this poll groups Independents together with Unenrolled’s, producing a far more accurate prediction as to how independent minded voters, both registered Independents and registered Unenrolled’s, will vote. This contrasts with previous polls mentioned below, which find Ms. Coakley besting Mr. Brown by separating Independents from Unenrolled’s and then excluding the voting preferences of these Unenrolled’s from the totals.)

If you had only accessed the Boston Herald for their report of this Suffolk University poll, you could have ended up as confused as the reporter, Jessica Van Sack. She writes, “Unenrolled long-shot Joseph L. Kennedy, an information technology executive with no relation to the famous family, gets 3 percent of the vote. Only 1 percent of voters were undecided.” See what she did? She called Joe Kennedy the “Unenrolled” candidate. He is not. Joe Kennedy, while often referred to in the press as an Independent Libertarian, is listed on the MA ballot as representing the Liberty Party.
http://www.sec.state.ma.us/ele/elespeif/senatorincongressmaelecan.htm
(Just to confuse you even more, when the Suffolk University poll asks voters for which candidate they intend to vote, it correctly refers to Mr. Kennedy as the Liberty candidate. But when it asks voters for favorability ratings, it calls him the Independent candidate.)

Contrary to the designation ascribed to Mr. Kennedy in the Boston Herald report on this just-released poll, there is no Unenrolled Party. In Massachusetts, there is only a category of registered voters not aligned with any party; these voters are registered Unenrolled. Yes, Unenrolled voters tend to be independent minded; but this does not make them members of either the Liberty Party or the Independent Party.

Read the Suffolk University summary. They got it right, even if the Boston Herald did not.
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I think I might have ‘figured out’ ‘what’s up’ with the apparent disparity in 2 (two) of the recent polls for U.S. Senate in Massachusetts.

Results of the latest Boston Globe poll put MA AG Martha Coakley up by 15 points in the race for U.S. Senate against State Senator Scott Brown. This hit me as really odd. The PPP poll just out put SB up by 1! So, I investigated further. I saw, the Globe poll ran from January 2-6 and has a margin of error of 4.2 whereas the PPP poll ran from January 7-9 and has a margin of error of 3.6. (Generally, the larger the sample, the smaller the margin of error.)

(The Globe runs liberal and PPP is paid for by the D Corporation, so I discounted the political bias as effecting these skewed results. And they both used likely voters, which tends to make the poll more reliable.)

In other words, in order to figure out what the skewed results in these 2 polls mean, I considered factors such as who paid for the poll; what was the sample used; whether this was a one-shot poll or a rolling poll, taken over a few days (and look at those days); and what was the margin of error.

But questions posted on the blogosphere point to another problem with accurately interpreting these polls as an indicator of voter preference.

Texasdarlin writes,

I am confused by the party affiliations cited in the Globe poll. I’ve seen on various blogs and news sites that the percentage of independents included in the Globe poll was very low (around 18%), but that’s not how I read their tables.
Can anyone double-check this and figure it out? Here is the survey:
http://www.boston.com/news/politics/2010/senate_race/0108010_poll_senate_race/

http://texasdarlin.wordpress.com/2010/01/10/boston-globeuniv-nh-coakley-up-by-15-really/#comment-112419

And Hot Air writes,

The new Boston Globe poll showing Democrat Martha Coakley beating Republican Scott Brown by 15-points in the race for Ted Kennedy’s Senate seat, when contrasted with Public Policy Polling showing a dead heat, has people scratching their heads. So what’s up with that?

http://hotair.com/greenroom/archives/2010/01/10/whats-up-with-the-mass-senate-polls/

I think I figured out what happened to MA Independents in these polls, too.

The Globe poll asks this question (p.3): ‘Are you registered D, I, R, or something else?’ How would you answer if you were registered as “Unenrolled”?

Massachusetts has a category of voter Registration called “Unenrolled.” The biggest difference in these categories is this: Independent voters may vote only in elections but Unenrolled voters may vote in primaries, too. They declare which ballot they want; vote; and leave the voting booth an Unenrolled voter, the same registration status they held when they went in.
http://www.sec.state.ma.us/ele/elespeif/us_senate_info.htm

When pollsters asked Unenrolled voters who participated in the Boston Globe poll, ‘Are you registered as D, I, R, or something else,’ these voters would have answered, ‘something else,’ right? However, the answer categories to this question are D; I/Unaffiliated; R; and Other. Did you catch that? The “I” in the answer category includes a designation “Unaffiliated,” but the I in the question does not include this word. So, when pollsters polled Unenrolled voters who answered “something else,” these responses likely were recorded in the category that reads, “Other.” This means that, the “I/Unaffiliated” answer category would only count those voters who answered that they were registered “I’s” but it would not count those independent-minded registered Unenrolled voters who answered “something else.”

And more than 50% of registered voters in Massachusetts are Unenrolled.
http://www.sec.state.ma.us/Ele/elepdf/st_county_town_enroll_breakdown_08.pdf

Looks like perhaps the Globe undercounted those independent minded voters who are registered as Unenrolled.

On the other hand, the PPP poll specifically categorized Independent/Other as a single grouping. Thus, “Independents” in the PPP poll would include all of those voters registered as both “Independent” and as “Unenrolled.”


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