Analytical and argumentative essays require different approaches. When you're asked to analyze something, for example a piece of literature, you are being asked to examine and evaluate the work to answer some how or why questions. When you're asked to make an argument, you must investigate a topic, collect, generate and evaluate evidence, then establish a position. In both cases, the thesis statement should always communicate to your reader what to expect from your essay.
General Analytical Thesis Statements
An analytical essay explores and attempts to answer the hows or whys that emerge with a particular topic or issue. Analyzing requires you to break down a subject into its component parts for examination, so your thesis statement should not only present your topic, it should also communicate how you will analyze it. Essentially, the reader should understand the relationship among the components being examined and how those relationships reveal something about the issue.
Literary Analysis Thesis Statements
In a literary analysis essay, you're still answering a how or why question, but you're answering those questions by examining elements of a piece of literature. This may require you identify a major theme and show readers how this theme is prevalent in the work, why the author presents this theme to readers or maybe how this theme impacts the plot and character development. For example, “The fate of the main characters in Sophocles' "Antigone" illustrates the dangers of excessive pride.” In this thesis statement, you have a theme, fate, and the literary work, "Antigone," and your analysis should show readers how fate affects the development of the work. Because your readers know what to expect, they can more easily navigate your analysis.
General Argumentative Thesis Statements
When writing an argumentative essay, a clear and defined thesis statement should explain why the topic is important and why readers should care. The thesis statement should not be so broad that readers cannot identify your position, nor so narrow that your position cannot fully be argued. If an argumentative thesis statement doesn't assert a defined position on an issue, the essay fails to achieve the goal of argumentation -- the reader cannot agree or disagree with a statement that isn't arguable. For example, this thesis statement presents no argument for reader to ponder: “Considering its geological position, Turkey has an important geopolitical role in the EU.” This is a fact, not an argument. A better thesis statement would read: “Considering its geopolitical role in the European Union, the EU clearly cannot survive without Turkey.” Here, the author presents an argument that must now be defended.
Similarities of Argumentative and Analytical Writing
Whether writing an analytical or argumentative essay, the thesis statement should always be arguable, clear and concise. If the thesis statement does not clearly communicate the topic and purpose of the writing, your readers may feel confused as to the direction or purpose of your essay. Another similarity is the need for research. Before writing either an analytical or argumentative essay, it's important to do your research, especially if the topic is complex. The more facts at your disposal, the better informed you are and the better argument or analysis you can achieve.