A thesis is a one-sentence (or occasionally a two-sentence) statement of your central idea. Usually your thesis will appear at the end of the first paragraph, but if you need to provide readers with considerable background information, you may place it in the second paragraph.
The thesis of your paper will be a reasoned answer to the central question you pose. Here is a research question posed by Ned Bishop, a student in a history course, followed by a thesis that answers the question.
RESEARCH QUESTION
To what extent was Confederate Major General Nathan Bedford Forrest responsible for the massacre of Union troops at Fort Pillow?
POSSIBLE THESIS
Although we will never know whether Nathan Bedford Forrest directly ordered the massacre of Union troops at Fort Pillow, evidence suggests that he was responsible for it.
Notice that the thesis expresses a view on a debatable issue—an issue about which intelligent, well-meaning people might disagree. The writer’s job is to convince such readers that this view is worth taking seriously.
Bishop, “The Massacre at Fort Pillow: Holding Nathan Bedford Forrest Accountable”
Exercise: Thesis statements in Chicago (CMS) papers 1
Exercise: Thesis statements in Chicago (CMS) papers 2
Related topics:
Drafting a working thesis
Forming research questions in various disciplines