Design artifacts such as sketches, wireframes, visual mockups, and prototypes are the essence of what interaction designers use to communicate their work. However, not all deliverables have equal scope. Instead, each deliverable type mentioned covers an area of the design space that is smaller or larger as they represent less or more screens.
What’s more interesting is that once the scope is broken up and varied across these various types of deliverables, they can begin working together in a hierarchy to serve different goals. Sketches are used to explore the breadth and flow of the interface as they unify the largest numbers of screens with user scenarios or stories. Visual design mockups are used to test the visual style details for a couple of page types. Finally, prototypes are used to test experimental page level interactions and convey the feeling of rich interactivity to get stakeholders excited about a particular concept. Taken together, each deliverable only needs a uniquely defined scope to fulfil its purpose.