Carolyn Snyder defines paper prototyping as a method of brainstorming, designing, creating, testing and communicating user interfaces. She simply explains how does it work.
You meet members of your team to choose the type of user who represents audience for the interface. You also determine tasks you expect this user to do. Then you sketch on the paper all the windows, menus, boxes pop-up messages which are needed to perform those tasks. The most important thing is, you don’t have to have a working version of the interface. You use whiteboard or make a paper prototype.
After you have a prototype, it is a time to conduct a usability test. You bring in a person who is representative of the audience. This user will attempt the tasks by interacting directly with the prototype – click by touching buttons etc. One person from the team is playing the role of “Computer,” manipulating the pieces of paper to simulate a computer. Another person is facilitator who conducts the session.
One of the graph from the book shows survey from 2002 among usability professionals. “What is the importance of paper prototyping to your work?” Answer: 15% told it is marginal, 56% useful, 30% essential and 0% useless.