Biases destroy Yale/George Mason University surveys

U.S. Main stream media duped on global warming polls

By —— Bio and Archives--October 28, 2012

Global Warming-Energy-Environment | Comments | Print Friendly | Subscribe | Email Us

In the past two weeks many U.S. media gave supportive coverage to two public opinion polls about global warming.  However, reporters were duped. The surveys released on October 9th and 18th by the Yale Project on Climate Change Communication and the George Mason University Center for Climate Change Communication were hopelessly biased. They therefore cannot be meaningful measures of American public opinion.


Conducting surveys that reflect a population’s real views on global warming is difficult. Because the idea that humanity is causing dangerous warming is promoted by most opinion leaders, and alternative viewpoints are condemned, most people are reluctant to express skepticism. They do not want to feel like social outcasts and so often give answers contrary to their actual opinions to conform to what they see as socially acceptable.

Researchers must try to overcome this “social desirability bias” by crafting questions so that opinions that are not fashionable are portrayed as equally acceptable as those that are more popular. They must also avoid:

  • Leading questions and statements.
  • Acquiescence Response Bias, the tendency for respondents to agree with statements no matter what their content. This is especially problematic in agree-disagree questions.
  • Expectancy Bias. If respondents perceive that the questioner has an expectancy of a certain answer, they are more likely to give that response.

The Yale/George Mason University polls commit all these mistakes.

The two questions most highlighted in their first poll, Climate Change in the American Mind, were:

  1. “How much do you agree or disagree with the following statement: “Global warming is affecting weather in the United States””
  2. “Some people say that global warming made each of the following events worse. How much do you agree or disagree?”

Since they are both agree-disagree questions, they clearly result in Acquiescence Response Bias, boosting the case for public belief in a global warming/weather connection.

Both of these questions are poorly formulated also because each assumes that respondents accept that global warming is happening. But the U.K. Met Office data released earlier this month demonstrates that there has been no overall warming for 16 years. Since all of the events listed as choices for question #2 occurred in the past two years, “global warming” could not possibly have made them worse.

So the most important questions in the first poll make no sense. They are also leading questions since they imply that the pollster believes that we in a warming phase. This then activates the problem of Expectancy Bias.

The second Yale/George Mason survey, “Climate Change in the American mind – Americans’ Global Warming Beliefs and Attitudes in September 2012”, is even worse.

The preamble to the first and most important question starts:

“Recently, you may have noticed that global warming has been getting some attention in the news.’

This is a leading statement. It implies that opinion leaders think global warming is happening; otherwise why give it attention? This amplifies, instead of overcoming, social desirability bias.

The preamble continues by defining global warming as “the idea that the world’s average temperature has been increasing over the past 150 years …”

But everyone who knows anything about climate history agrees that it is warmer now than in the mid-nineteenth century. Otherwise we would still be in the Little Ice Age.

ICSC Chief Science Advisor Professor Bob Carter of James Cook University in Australia adds, “Whether it’s warming or cooling is entirely a function of the length of the piece of climate string you choose to cut off.”

Here are different start dates that survey coordinators could have used and the resultant temperature trends to the present:

  • Since 1998, slight cooling.
  • Since 1996, neither warming nor cooling.
  • 1980, slight warming
  • 1,000 AD, cooling
  • 600 AD, warming.
  • 150 BC, cooling
  • 1,350 BC, cooling.
  • 2,800 BC, warming.
  • 4,000 BC, cooling.

The second part of their global warming definition is that it “refers to the idea that the world’s average temperature …may be increasing more in the future.”

But temperatures may also fall in the future so this is not a definition of anything.

In the last part of their definition of global warming the Yale/George Mason pollsters say that “the world’s climate may change as a result” of temperature rise.

But since temperature is an important part of climate, this is like saying that climate change may result in climate change.

With most of the October 18th report and survey based on this Alice in Wonderland-like definition of global warming, we have no choice but to dismiss as meaningless the answers to their subsequent question “Do you think that global warming is happening?”

Finally, the Yale/George Mason University polls failed to ask the two most important questions in the whole debate:

1. “Which of the following do you think is true?”

  • Carbon dioxide from human activities will most likely cause dangerous climate change in the foreseeable future.
  • Human produced carbon dioxide is unlikely to cause dangerous climate change in the foreseeable future.
  • No opinion/don’t know.
  • It must be “dangerous” change that is being asked about. If it is not dangerous then, while it is an interesting issue for researchers, it should not be a public policy concern at all, let alone worth billions of dollars trying to fix. 2. “How much of an increase in your cost of living would you accept to reduce carbon dioxide emissions?” Until these questions are asked in a bias-free way, no public opinion poll about global warming, least of all this month’s surveys, should be taken seriously.


Only YOU can save CFP from Social Media Suppression. Tweet, Post, Forward, Subscribe or Bookmark us

Tom Harris -- Bio and Archives | Comments

Tom Harris is Executive Director of the International Climate Science Coalition.

Older articles by Tom Harris

Commenting Policy

Please adhere to our commenting policy to avoid being banned. As a privately owned website, we reserve the right to remove any comment and ban any user at any time.

Comments that contain spam, advertising, vulgarity, threats of violence and death, racism, anti-Semitism, or personal or abusive attacks on other users may be removed and result in a ban.
-- Follow these instructions on registering: