September 23, 2010

SIUC expert to discuss ‘What makes a good poll?’

by Pete Rosenbery

CARBONDALE, Ill. -- An in-depth look into polling by a public opinion researcher will serve as a political primer next week at Southern Illinois University Carbondale’s Paul Simon Public Policy Institute.

Charles W. Leonard, a visiting professor and director of the Institute’s polling initiatives, will offer insights into how polls are designed, conducted, and reported, and how to tell if a poll is accurate, when he presents “An Insider’s Guide to Polling: What Makes a Good Poll?”

The presentation is at 4:30 p.m., Sept. 30, in the Institute lobby. The event is free and open to the public but advance registration is required. To register, contact Institute project coordinator Christina Rich at 618/453-4078 or by email at by Tuesday, Sept. 28. The event is an expanded version of the Institute’s informal “Pizza and Politics” series.

“Charlie’s session will be good for anyone interested in learning more about polls,” Institute Director David Yepsen said. “It will be useful to the political junkie watching this campaign and students who need to know more about public opinion research.

“Polls are an important tool in politics and in public policy research but a lot of people don’t understand them and sometimes they are misused,” he said. “Charlie teaches courses about this subject and he’s worked in it in the private sector so people should get a lot of good information in a two-hour session.”

Leonard will give a basic overview of the statistical theory behind public opinion polling, and how and to what extent it applies to real-world political behavior. Leonard said he will also discuss the steps needed to put a together a good poll, and also how to spot a “bogus” poll.

“This is a way for people to be informed consumers of election information -- to try to lift the curtain on the polling business so people can be an independent judge about the quality of information they get,” he said.

Leonard emphasized that polls are a snapshot of a particular moment of voter opinion, not necessarily a predictor of future outcomes.

“People make two kinds of mistakes in evaluating polls,” he said. “They either think they are all wrong and cannot be trusted or they take all polls at face value. I want to explain to people what they are good for, what they can do within certain limits, what polls can’t do, and how to take polls with a grain of salt.”

Leonard will also discuss a poll’s margin for error, how exit polls work, and how various communication technologies, including answering machines, caller ID, and cellular telephones, impact polling. He will also discuss how to draw a good respondent sample for polls.

“If you draw a good sample everything else will take care of itself,” he said.

Leonard emphasized it is important for the media to have a rudimentary understanding of statistics to report precisely on what polls do and do not reflect.

Before coming to SIUC in 2007, Leonard was a faculty member at the University of Texas at Dallas, where he also was director of The Eugene McDermott Scholars Program. A former newspaper and magazine editor, Leonard’s experience also includes serving as director of research for Attitude Research Company in St. Louis. Leonard teaches courses in American government and public policy in SIUC’s Department of Political Science.

For more information, contact the Institute at 618/453-4009 or visit