Conflicting Sources

When you're dealing with research, you'll often encounter conflicting information. How can you handle it?

Matters of Fact
Sometimes sources will give different information about matters of fact. For example, some say the Pilgrims left England on Sept. 6, 1620, while other sources give a day 10 days later. Is there some question about when the Mayflower actually sailed? No, England adopted a new calendar in 1750, which led to double date confusion.

Some discrepancies can't be resolved, however. In that case you can either

use the source that is generally considered most reliable
tell readers about the contradictions and explain how they affect your argument

Statistics and Studies

People tend to trust statistics. But the reliability of numbers can be affected from everything from how the data is gathered to how the results are graphed.

John Allen Paulos is a mathematician who debunks widely reported, but misleading, numbers. Are 3 million illegal immigrants really entering the United States each year? Not according to Paulos. Border agents detain about 1 million people each year; they estimate that they catch only 1 in 3 of the people trying to cross the border. So the number is based on a guess. It also doesn't account for the fact that some people are arrested more than once. (For the story of another guess, see Bogus Research Uncovered.)

When using statistics, ask

Do the numbers seem reasonable?
Are they from a credible source?
Were they gathered in an unbiased manner?
Do they really measure what they say they're measuring?
Do they tell the whole story? (See Harvard Business School's Five Guidelines for Using Statistics in business.)
Are they accepted by experts in the field? (See this review of studies that supposedly prove that capital punishment deters crime.)

Conflicting Sources

Sometimes two sources flatly contradict each other. For example, antismoking activists claim that studies prove secondhand smoke is harmful to nonsmokers, while the tobacco industry argues that these studies are flawed. In that case, consider

What is the source of the evidence? Is it likely to be biased or faked? (See Armstrong's article on how doctors' ties to drug industry cloud the issue of whether preganant women should take antidepressants.)
Is there outside evidence that supports one of the sources?
How do the conflicting sources fit with what else you know about the topic? (for example, the tobacco industry has been accused of suppressing research about the harmful effects of tobacco).

If you can't decide which information is more reliable, you might combine them:

The actual number of hate sites is in itself open to debate. Estimates can range anywhere between 400 to 1,200.

"Different groups have different ways of counting," said Anti-Defamation League spokesman Jordan Kessler said. "(The definition) can include hardcore, white supremacy sites or just a page filled with insensitive jokes" (Chaudhry, 2000).

You can also indicate that numbers or dates are not exact:

Sophocles was born circa 496 BCE in Colonus..... He died approximately 90 years later, circa 406 BCE....

Conflicting Opinions

Reasonable people can disagree about controversial issues like stem-cell research or capital punishment. In that case, you'll have to use critical thinking to weigh the arguments.

Which source is most credible?
Can you identify any fallacies in the arguments?

Internet Resources

	Finding Pro-Con Opinions
	Evaluating Conflicting Sources (National History Day)
	20 Questions Journalists Should Ask About Poll Results (Public Agenda)
	How to Lie with Statistics: And Know When You're Being Lied To (Hugh Kramer)
	Making Sense of Evidence (primary sources and statistics)
	The Problems with Statistics (Taflinger)
	Reliability and Validity (Colorado State)
	Resolving Conflicting Genealogy Data (Lisa South)
	Scandals: Contemporary Legends—How to Lie with Statistics
	Statistics Every Writer Should Know (Robert Niles)
	Who's Counting? (column by John Allen Paulos)

Copyright in these materials belongs to C. Munzenmaier © 2007.
Teachers are free to reproduce or modify them for nonprofit educational use.

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	C. Munzenmaier • Hamilton College • Urbandale, IA