What do you do when you are not the subject expert? In several projects, I have involved experts, users and stakeholders, to become part of the design process. Since they are expert of their experience they can bring valuable ideas and content to the sketching table.
In many projects I use co-creation to validate information, come up with ideas, refine concepts or test ideas.
For an innovation project with the Singapore National Eye Center we used co-creation to validate the research outcomes and to come up with service ideas. We also used it towards the end to refine the design of several concepts.