What's within a thesis statement? Exploring features of argumentative thesis statements

Developing strong academic writing skills often requires years of experience and training within a discipline. When novice writers are asked to write an argumentative essay, they are usually required to draft a thesis statement presenting their position on an issue. In argumentative writing, a thesis statement addresses the writer's main argument and is the foundation of the entire essay. Features of thesis statements are often defined with respect to their location and length within the essay (e.g., Petric, 2005), or functions. As a result, further research exploring characteristics of argumentative thesis statements could expand understanding about the distinctive features that operationalize the quality of thesis statements. Results of such research would have strong practical implications for instructors regarding what to teach about writing thesis statements. In the present study, four major features of thesis statements were identified (context, positionality, reasoning, and specificity). Two raters were asked to assess the presence of each feature for the 78 thesis statements, extracted from the argumentative essay outlines of an education course. A set of multiple regression analyses were conducted to investigate whether each feature, and a composite of the four, contributes to the quality of the introduction and the argumentative essay outline. Key findings indicated that the context feature and the positionality feature are of importance in predicting the quality of introduction and the essay outline. Based on the findings, a revised version of Ken Hyland's model of argumentation is proposed and several important implications for teaching writing are recommended.