More often than not, system dynamics model-based public policy analysis is limited to testing parameter changes instead of designing and testing new stock-and-flow policy structures. That is problematic because improvements in behaviour require improvements in structure. This paper considers how the public policy implementation literature could improve the operational thinking skills required for designing policy structure for public sector models. A familiar model of a public health problem is used to illustrate the recommended approach. And an instructional training strategy is offered for teaching and learning to think operationally during the policy-design stage of modelling. Copyright © 2010 John Wiley & Sons, Ltd.