A thesis statement is usually a single sentence either at the beginning or end of the first paragraph of an essay that directly answers the question asked and tells the reader how the writer will interpret the significance of the subject matter. It usually makes a claim that others might dispute and the rest of the essay involves gathering and organizing evidence to prove the writer’s interpretation, so the thesis acts as a road map for the paper. Thesis statements should generally be clear, specific, demonstrable and state the essay’s subject and purpose.
An essay usually asks a specific question, and the thesis statement ought not to be too broad or vague but should specifically answer the question. It should have a narrow focus and not touch on multiple ideas. Instead, a writer should assert one main idea that captures the logic applied throughout the essay. Avoiding the use of over-generalized, vague or abstract terms and phrases also helps in coming up with a clear and specific thesis statement. Words such as ‘many’, ‘most’, ‘all’, ‘everyone’, ‘interesting’, or ‘difficult’, can be qualified and using them may result in a thesis statement that cannot be supported in the essay. For example, if the essay topic is about obesity in America, ‘Many Americans are suffering from obesity because of their diet’ is an overly-generalized statement and a better one would be ‘Excessive consumption of fatty and sugary foods is the leading cause of obesity among Americans’.
A good thesis statement does not simply state a fact, but it makes a claim that can be discussed or explored further in the essay. The statement should present the writer’s point of view based on his understanding of the topic question and initiate an argument that will be supported throughout the rest of the essay. For example ‘The American civil war was fought because of differences between the North and South’ is stating a fact, but a debatable claim would be ‘While both Northerners and Southerners believed they fought against tyranny and oppression, Northerners focused on the oppression of slaves while Southerners defended their own right to self-government.' In order to come up with a single sentence that surmises the essay arguments, the writer needs to really have researched the topic so that he has in-depth knowledge and can concisely guide the reader on the subject matter.
The claims made in a thesis statement must be supported through the sources cited in the essay. Writing an essay requires the writer to read a variety of secondary resources and come up with an original argument that persuades the readers towards his interpretation of the topic. Therefore, in writing a thesis statement, the writer ought to refrain from referring to ideas that are not supported in the essay, instead using principles or theories obtained from the sources and relevant examples to illustrate the point.
The thesis statement ideally should state the purpose and scope of the essay such that it influences the nature of content. The author should consider what he wishes to communicate to his audience and bring it out in the statement. For example, an essay could seek to be entertaining, thought-provoking or informative and the thesis statement spells out exactly what the writer wishes to accomplish. However, it may be necessary to revise the thesis statement to reflect evolving ideas as the writer develops the content.