Fighting Statistical Illiteracy

AP Misreads Percentage Table

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10/22/09: The Associated Press (AP) released a story, Belief in Global Warming is Cooling, that said:

  • 57% of Americans said [yes] there is solid evidence that the earth is warming [a 14 point drop from 2008]
  • 36% [of Americans] said temperatures are rising because of human activity [an 11 point drop from 2008]

 The AP also released this graph (AP ID: 09102201574) that described the 36% differently:

  • 36% of those who answered yes, said temperatures are rising because of human activity


Now, 36% of 57% is around 20%.   So according to this AP graph, only 20% of Americans said temperatures are rising because of human activity.  This 20% would be big news if it were true.    Both AP interpretations of the 36% came from this table. 


Source: Fewer Americans See Solid Evidence of Global Warming by The Pew Research Center for the People & the Press.   Notice that this table is a multi-level percentage table: the percentages add to more than the totals and some of the rows are indented.  Percentage tables are not always easy to read – even by professionals.

 On 10/23, the AP released a second graph (AP ID: 0910222617) that deleted the 36% description used in their first graph.  


Did the AP make the right decision?   What do you think and why?

Written by schield

October 25th, 2009 at 5:21 pm

Posted in Ratios

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