Most research papers are structured around persuasive argumentation, so the introductory paragraph needs to initiate the argument itself. The introduction should state the general content of the paper, why the reader should be interested in reading it and where the information contained in the paper ultimately leads.
Along with providing a general introduction to the topic at hand, the introduction should contain a thesis statement, which conveys the author's general point. The introduction, to some extent, also presents a summary of the research's conclusion. Additionally, the introduction should outline the ensuing content and organization of the paper. For example, if the paper has several recognizably autonomous sections, the introduction can briefly enumerate each, along with why their chosen order of presentation supports the already offered thesis statement.
The author should remember that thesis statements are never statements of absolute fact, nor are they simply restatements of the subject. They are statements of qualified opinion, given persuasive support by the content and structure of the research paper. Thus, the statement "Jane Austen authored Pride and Prejudice" is not a thesis statement, whereas "parents need to be more involved in their children's education" and "detective stories appeal to the basic human desire for thrills" are thesis statements.