If you want to understand how someone thinks your product works, give them a pencil and ask them to draw you a diagram.A simple sketch can transport you inside someone else’s head better than any other product research technique.Sketching is awesome at helping us construct new ideas and communicate them to others. It’s no coincidence that many product designers’ software of choice for constructing their ideas is called “Sketch”. This post is not about that type of Sketch.

Source: Understanding your users’ mental model – Inside Intercom