|Graphic by Keith Bishop|
"The best polls are produced by independent, nonpartisan polling organizations, with no vested interest in the outcome of the findings," Kille writes. "These include organizations like Gallup and the Pew Research Center and as well as media groups such as CBS News/New York Times, ABC News/Washington Post and NBC News/Wall Street Journal."
"Many surveys are conducted by partisan actors—political consulting firms, industry groups and candidates," Kille writes. "In some cases, the findings are biased by factors such as respondent selection and question wording. Partisan-based polls need to be carefully scrutinized and, when possible, reported in comparison with nonpartisan poll results."
"It’s important to remember that polls are a snapshot of opinion at a point in time," Kille writes. "Despite 60 years of experience since Truman defied the polls and defeated Dewey in the 1948 presidential election, pollsters can still miss big: In the 2008 Democratic primary in New Hampshire, Barack Obama was pegged to win, but Hillary Clinton came out on top. A study in Public Opinion Quarterly found that 'polling problems in New Hampshire in 2008 were not the exception, but the rule.' In a fluid political environment, it is risky to assume that polls can predict the distribution of opinion even a short time later."
Tips for reporting on polls can be found here.