Planning and public policy endeavours are argumentative. We explore issues in analyzing and learning about planning and policy argumentation by considering the use and misuse of Toulmin's method of argument representation. We first outline Toulmin's heuristic and its contributions, then discuss the dangers of converting it into 'the Toulmin model'. From examples in published literature and from classroom experience, we suggest that there is widespread misunderstanding and misuse of the model, including: (1) oversimplification of complex argumentation by trying to squeeze everything into a single simple diagram: (2) much mistaken identification of components; (3) treatment of the introductory Toulmin diagram as if it could be a layout equally suitable for every argument; and (4) possible discouraging or misleading of users because of an unwieldy and perhaps counterintuitive visual presentation. We suggest as practicable ways to increase effective use: (a) employment often of multiple linked diagrams rather than a single one; (b) a more systematic, multistage, coding process to identify argument components; (c) more flexible handling of layout, responsive to the specificity of particular arguments; (d) use sometimes of tables rather than diagrams. In addition, going beyond the Toulmin model, we advise attention to more flexible general approaches for specifying argument structure, to approaches with more policy-analysis and planning content, and to other aspects of argumentation analysis.