What should an effective thesis statement include?

An effective thesis statement should include an arguable claim because it serves as the central argument or position that the writer will support throughout the essay. An arguable claim provides a clear focus for the paper, guiding the direction of the discussion and analysis. This claim should be specific enough to be discussed in detail, allowing for the presentation of evidence and reasoning that will substantiate it in subsequent sections of the essay.

In contrast, a summary of the entire essay does not provide a focused claim but rather an overview, which is not suitable for a thesis statement as it doesn't present a debatable point. Detailed evidence, while essential for supporting the thesis later in the essay, does not belong in the thesis statement itself, which should remain concise and focused on the main argument. Historical background can be relevant in certain contexts, but it should not be included in the thesis statement, as the purpose of the statement is to articulate the argument rather than provide context.