The headline on an October 9 press release from the Yale Project on Climate Change Communication and the George Mason University Center for Climate Change Communication read: “Poll Shows Americans Believe Global Warming Is Making Extreme Weather Worse.”
Mainstream media quickly reported uncritically on the poll. The Chicago Tribune ran a reproduction of a Reuters newswire: “Most Americans Link Weather to Global Warming: Survey.” At the Huffington Post: “Climate Change Survey Shows Most Americans Believe Warming Is Tied To Extreme Weather Events.”
But did the poll – ”Climate Change in the American Mind“ — actually demonstrate this?
To evaluate the significance of the survey results, we must compare the methodology employed by the researchers with that needed to generate meaningful results about this complex and controversial topic.
Conducting surveys that measure real public opinion about global warming is difficult. Because the hypothesis that humanity is causing dangerous warming is now loudly supported by most opinion leaders — media, educators, and government — and alternative viewpoints are condemned, most citizens are reluctant to express skepticism about the issue despite what they actually think. The public will often give answers contrary to their opinions so as to conform to what they believe is socially acceptable concerning issues on which the politically correct position is clear.
Researchers must attempt to account for at least some of this unavoidable “social desirability bias” in global warming polling by crafting questions so that opinions not currently fashionable are portrayed as acceptable. They must also avoid well-known biases that are completely within survey coordinators’ control by steering clearing of certain problems:
- Writing leading questions. A question’s wording must not be structured so as to unduly favor one answer over another. Questions should also not present as implied fact information that is under dispute.
- Acquiescence Response Bias. This is the well-understood tendency for poll respondents to agree with statements no matter what their content. This problem is especially pronounced in polls that include agree-disagree questions. Research has shown that the least educated and least informed respondents are most likely to agree with statements presented in this way.
A Pew Research Center experiment (see p. 26 here) demonstrates the impact of Acquiescence Response Bias. Respondents were asked whether they agree or disagree with the following statement: “The best way to ensure peace is through military strength.” 55% agreed. 42% disagreed. When respondents were given a choice — “The best way to ensure peace is through military strength,” or “Diplomacy is the best way to ensure peace” — only 33% supported the military strength option while 55% supported the second choice.