Supporting details are reasons, examples, facts, steps, or other kinds of evidence
that explain a main idea.
Look at the following cartoon.
In the cartoon, the main idea is that reading the morning paper is bad for the man’s health.
The supporting reasons are that the political news raises his blood pressure, the business
report makes him depressed, and the sports page makes him mad.
Now take a look at the following paragraph:
Eight million more women than men are of voting age, and more women than men vote in U.S.
national elections. However, men greatly outnumber women in political office. Since 1789, over
1,800 men have served in the U.S. Senate, but only 30 women have served. Women are underrepresented
in U.S. politics for a number of reasons. First, women are still underrepresented in
law and business, the careers from which most politicians emerge. In addition, most women
find that the irregular hours kept by those who run for office are incompatible with their
role as mother. Fathers, in contrast, whose ordinary roles are more likely to take them
away from home, are less likely to feel this conflict. Last, preferring to hold on to their
positions of power, men have been reluctant to incorporate women into centers of decision-making
or to present them as viable candidates.
The main idea is “Women are underrepresented in U.S. politics for a number of reasons.”
Take a minute to see if you can pick out the three reasons that are given to
support this main idea.
There are three reasons that support the main idea. Notice that each is marked by words
that signal major details. These words, also known as addition words, are
“First,” “In addition,” and “Last.” Looking for addition words such as these can help
you find supporting details for a main idea. Here are some common addition words:
one for one thing
in addition first of all
another last
second also
finally
Addition words will often help when you study a paragraph by outlining it.
Here is a quick review of outlining.
An outline helps you understand and see clearly the relationship between a main idea and its
supporting details. Outlines start with a main idea followed by a numbered list of supporting
details. Here is an outline of the paragraph about women.
The main idea is that women are underrepresented in U.S. politics.
The first reason is that women are still underrepresented in law and business,
the usual starting for politicians.
The second reason is that a politician’s
hours are incompatible with the role of a mother.
The third reason is that men have been reluctant to give women power.
Now let’s look at a helpful outlining tip.
Here are some common list words that tell you a list of details is coming:
several kinds of various causes
a few reasons a number of effects
a series of three factors
four steps among the results
several advantages
In the paragraph on women we’ve already looked at, you’ll note that list words were
used that signaled the main idea:
Women are underrepresented in U.S. politics for a number of reasons.
Once we saw “a number of reasons,” we could guess that a list of supporting reasons
was about to follow.
In addition to using outlines, you can also use maps to show the relationship between
a main idea and its supporting details.
Maps, or diagrams, are highly visual outlines in which circles, boxes, or other shapes show
the relationship between a main idea and its supporting details. Here is a paragraph we
considered in the first chapter:
People lie for different reasons. One common reason is to avoid hurting someone’s feelings.
For example, a friend might ask, “Do you like my new haircut?” If you think it’s
ugly, you might still answer something like, “I really do.” Another common reason for
lying is to avoid a fight. Say a friend angers you and then asks, “Are you upset with me?”
You might answer, “No,” to avoid an argument. People also lie so that they’ll fit in,
as when you listen to a boring person and politely say, “That’s so interesting.”
Finally, people lie to avoid spending more time with someone. For instance, you might
lie, “I have to go now.”
Here is a map of this passage. You’ll see how it sets off the major details in a very
visual way.
The point is that people lie for different reasons: to avoid hurting feelings; to avoid
a fight; to fit in; and to avoid spending time with someone.
To summarize, then, a skilled reader is one who looks for the main idea or point of a
selection as well as the support for that main idea.
Ask yourself, “What is the point of a selection?” as well as “What support is offered for
the point?” Then use outlining and mapping as ways to set off clearly the main idea and
its support. The very act of outlining or mapping helps you deepen your understanding
of a selection.