The uses and complexity of argument structures in expert and student persuasive writing

This study investigated differences among student writers at three grade levels (6, 8, and 10) and between expert writers and students in terms of the uses and complexity of arguments presented in their persuasive texts. To analyze argument, a model was developed that could account for structural variations occurring across a range of writing situations. The characteristics of this model were defined using categories derived from a model of semantic representation in discourse. The structural analysis revealed that (a) argument was the predominant organizational structure for all writers, (b) more than 80% of students produced arguments involving some form of opposition, (c) embedded arguments identified in expert tests functioned primarily as countered rebuttals and in student texts as subclaims or reservations, and (d) expert texts contained relatively higher frequencies of warrants, countered rebuttals, and modals, and student uses of these substructures increased with grade.