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Tuesday, January 22, 2013

"Polling-tics" for Americans

It’s a long way from the banner headline “Dewey Defeats Truman” in the Chicago Tribune.
  I’m not talking about politics and the press, but about polling, which most Americans are probably sick of about now. Back in 1948, public opinion polling was in its infancy, contributing to that journalistic fiasco.
The just completed inauguration of President Obama  concluded the 2012 election, where we were deluged with more polls than ever, and they remarkably foretold the results, correctly predicting the electoral outcome in every state.
How? Americans are justifiably suspicious of polling, but it is a fact of our lives, and not just in politics. This is a version of an article I wrote for the Oklahoma Press Association Publisher.
Forget the poo-pooers who argued with what the polls showed because they disagreed or didn’t want to believe, or thought they were biased.  Forget your political views of Huffington Post. But its poll aggregator of hundreds of polls nailed the results. 
It is a fact that most Americans don’t understand scientific polling, and I think it is up to newspapers to help make that clear as to what can be trusted and what can’t.
Hence, here’s 
 Prof’s Press Primer on Polling, Part One
Definition of terms is first.
  •    Population—The group to be surveyed, such as likely voters, residents of Hennessey, Thunder season ticket holders.
  •    Random—Random does not mean “haphazard.” It means that every person in the population has an equal chance of being chosen. It’s easy in a classroom—you put every name in a hat and have a few names pulled out. Bigger groups require phone numbers or addresses, all more easily available than ever with computer data.
  • Sample—The portion of the population to be chosen randomly to ask the poll questions
  •  Valid—A poll is valid if the results collected from the sample can be applied to the entire population.
  • Margin of error—Expressed as a plus and minus percentage. Every poll has flaws and variables that will affect the accuracy of the results, but the larger the sample, the lower the margin of error (If you poll everyone in the population there will be no margin of error, but that isn’t possible in most cases).
Now the key question—how big a sample do you need to conduct an accurate poll?
You’re not going to believe the answer. So first things first. Timing, wording of questions, training of the pollsters, polling methods, and other factors also affect a poll’s validity, not just the sample size. But sample size is not dependent on population size.
That said, to get a sense of how people in Stillwater might vote on any issue, or people in Oklahoma on another issue, or people in the United States,  for a five percent margin of error, you need roughly only 400 registered, or likely, voters selected randomly. Yep, that’s all.
Here’s how the margin of error figures. Suppose the results come back showing Panhandle residents favor seceding from the state by a 52-48 percent margin. The results are within the margin of error so the election could go either way—it could be 52-43, or 47-52, or any combination. If on the other hand it was 75-25, Oklahoma, you have a problem.
Most national polls try to have a sample of about 1,200 people—that produces a margin of error of about plus and minus three percent.
Also important in polling is the timing. A poll or electability two days after Romney winning the first debate is valid that day. But as fast as things change in this digital news country, it wouldn’t be valid in five days.
'Other factors can affect outcome...
you could live in Florida'
Other factors can affect outcome. People who say they will vote and don’t show up. Or a Hurricane could shut the place down. Or you could live in Florida.
As with everything in journalism, sources also matter in polls. Who conducted it?
But that’s a separate subject—tomorrow, an American’s checklist for evaluating a poll (should you believe it?)
Hint: USA Today once ran a story and headline at the top of the page about most American women wouldn’t remarry the same man, based on a Women’s Day survey. What was wrong with that? And why Romney was shocked that he didn't win.

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