Writing Analytically, 6th Edition - Rosenwasser, David & Stephen, Jill [117]
STATISTICAL EVIDENCE
Statistics are a primary tool—a virtual language—for those writing in the natural and especially the social sciences. They have the advantage of greater objectivity, and, in the social sciences, of offering a broad view of a subject. Remember, though, that like other forms of evidence, statistics do not speak for themselves; their significance must be overtly elucidated. And, as the fielding average example suggests, it should never simply be assumed that statistics are valid representations of the reality they purport to measure.
The following brief excerpt is from a study of factors that determine Americans’ views on global warming, written by Christopher Borick and Barry Rabe (in Issues in Governance Studies, No.18, July, 2008).
Excerpt from “A Reason to Believe: Examining the Factors That Determine Americans’ Views on Global Warming”
Since the 1980s, there has been a growing body of data that examines the perceptions of Americans regarding the issue of global warming. This data paints a picture of generally increasing recognition, acceptance, and concern in the United States regarding atmospheric heating of the earth (Nisbet and Myers, 2007).
In the past two decades, the number of Americans who have heard of the “greenhouse effect” has steadily increased.
In 1986, less than one in four respondents said they had heard of global warming. By 2006, over nine out of ten recognized the issue (Nisbet and Myers, 2007). A growing number of Americans believe that the Earth is already experiencing increased heating as Table One shows. […]
Public opinion research shows Americans are increasingly acknowledging global warming (Nisbet and Myers, 2007); however, what isn’t seen are the underlying causes of these beliefs. In particular, what type of evidence do Americans cite as having an important effect on their perceptions of global warming? Recent Pew Research Center polls have shown fairly significant short-term shifts in the number of Americans who believe there is evidence of global warming. Between June 2006 and January 2007, there was a 7% increase (70% to 77%) among U.S. residents who indicated there was “solid evidence” that the Earth is warming. However, between January 2007 and April 2008, the percentage decreased by 6% (77% to 71%). This decline in public acceptance of the evidence of global warming may be an aberration in a long-term trend of increasing belief. However, the shift does raise questions regarding the underlying factors affecting public acknowledgement of global warming. What types of evidence are individuals reacting to? [The writers note a significant short-term shift in views of Americans on global warming but then go on to frame a new research question about the kinds of evidence upon which individuals are basing their claims. This will in turn lead to further opinion polling and statistical analysis.]
Interpreting the Numbers: A Psychology Professor Speaks
In the following Voice from Across the Curriculum, psychology professor Laura Edelman offers advice on how to read statistically. She expresses respect for the value of numbers as evidence, as opposed to relying on one’s own experience or merely speculating. But she also advises students to be aware of the various problems of interpretation that statistical evidence can invite.
Voices from Across the Curriculum
The most important advice we off er our psychology students about statistical evidence is to look at it critically. We teach them that it is easy to misrepresent statistics and that you really need to evaluate the evidence provided. Students need to learn to think about what the numbers actually mean. Where did the numbers come from? What are the implications of the numbers?
In my statistics course, I emphasize that it is not enough just to get the “correct” answer mathematically. Students need to be able to interpret the numbers and the implications of the numbers. For example,