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Part V: Statistical Studies and the Hunt for a Meaningful Relationship
You know the saying “Seeing is believing”? Some researchers are guilty of the

converse, which is “Believing is seeing.” In other words, they claim to see what
they want to believe about the results. All the more reason for you to know
where the line is drawn between reasonable conclusions and misleading
results, and to realize when others have crossed that line.
Here are some common errors made in drawing conclusions from surveys:
✓ Making projections to a larger population than the study actually
represents
✓ Claiming a difference exists between two groups when a difference isn’t
really there (see Chapter 15)
✓ Saying, “these results aren’t scientific, but . . . ,” and then going on to
present the results as if they are scientific
To avoid common errors made when drawing conclusions, do the following:
1. Check whether the sample was selected properly and that the conclu-
sions don’t go beyond the population presented by that sample.
2. Look for any disclaimers about the survey before reading the results.
That way, if the results aren’t based on a scientific survey (an accurate
and unbiased survey), you’ll be less likely to be influenced by the results
you’re reading. You can judge for yourself whether the survey results
are credible.
3. Be on the lookout for statistically incorrect conclusions.
If someone reports a difference between two groups in terms of survey
results, be sure that the difference is larger than the reported margin of
error. If the difference is within the margin of error, you should expect
the sample results to vary by that much just by chance, and the so-
called “difference” can’t really be generalized to the entire population.
(See Chapter 14 for more on this.)

Know the limitations of any survey and be wary of any information coming
from surveys in which those limitations aren’t respected. A bad survey is
cheap and easy to do, but you get what you pay for. But don’t let big expen-
sive surveys fool you either — they can be riddled with bias as well! Before
looking at the results of any survey, investigate how it was designed and con-
ducted, using the criteria and tips in this chapter, so you can judge the quality
of the results and express yourself confidently and correctly about what is
wrong.

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