A thesis statement is the most important few sentences you will write in a thesis, research paper or any other essay that adheres to APA (American Psychological Association) format. In order to come up with your thesis statement and position it correctly in your paper, you will first need to settle on a topic and determine what kind of paper you are writing; then you will formulate the question that your paper addresses, prepare your thesis statement and position it in your paper in the appropriate format.

Select a Subject

You may have a topic assigned or you may find yourself responsible for coming up with your own topic for your paper; either way, you will need to narrow that topic down for your discussion. For example, if you need to write a thesis on "How the Home Environment Affects Child Development," rather than trying to broadly cover such a large topic, you'll want to narrow that topic down to a particular aspect of the subject, such as the physical environment of the home.

Determine the Type of Paper You Will Write

There are three types of papers you can write for a thesis: analytical, expository and argumentative. An analytical paper evaluates a position or idea by analyzing it in parts or in whole; an expository paper seeks to explain a topic or educate an audience and an argumentative paper will take a position on a particular subject and back it up with evidence. Select the type of paper appropriate for your approach to the topic; for example, you may chose to write an expository paper on the physical environment of the home and its consequences on child development to introduce the concepts involved to an audience unfamiliar with the subject.

Settle on a Question

You will need to ask, and answer, a specific question in order to write your thesis statement. In order to do this, you need to either come up with a question you can answer, or one which you can demonstrate does not yet have an answer and why. In the example of a paper on the implications of the physical environment on child development, you might ask a question such as: "Which features of the physical environment in a home have negative consequences on child development?" Depending on your survey of the literature available on the subject, you may either answer this question directly with your thesis statement or explain why this question does not yet have a scientifically valid answer.

Write and Position Your Thesis Statement

The most important aspects of your thesis statement are clearly and succinctly stating the question that guided your paper, giving your audience a precise answer to this question and briefly outlining the scope of the paper. Your thesis statement will need to follow a format specific to the type of paper you are writing; for example, an analytical paper, your statement might read as follows:

"An analysis of available research on the physical environment identifies three factors that should concern parents and the physical environment to which they expose their children: noise levels, crowding and neighborhood quality."

Positioning Your Thesis Statement

Once you compose your thesis statement, place the statement in the first paragraph of your paper; this to make your objective clear and well-defined. The thesis statement can either be the first few sentences of the paper or included as the final sentences in the first paragraph of your introduction. In APA format, this will be the first paragraph of your abstract.