Matt Ellis. Student Update. A thesis statement is a sentence in an article or essay in the opening paragraph that introduces the main topic. · Decide what type of article you will write. When you are assigned an essay, you may get several different types. Argumentative essays are as follows: A strong thesis statement is one that invites discussion and presents a debatable claim. Avoid stating obvious or universally accepted facts. Instead, try to present an argument or perspective that can be supported, challenged, or explored further in your essay. A questionable thesis statement stimulates critical thinking and engages your,