A preliminary thesis statement, also known as a working thesis statement, is the initial thesis used to guide an individual's research. A well-written preliminary thesis statement identifies the topic being studied and suggests how the research is to be organized. It is no more than one or two sentences long.
The purpose of a thesis statement is to give a research topic focus; however, it is important for a researcher to remain flexible and open. Though a researcher may begin with a preliminary thesis statement, as the research develops and information expands, he may alter the final thesis statement to coincide with the changed direction of his research.