Use scenarios and personas help you explore your design by making more concrete the people who will use your design and the types of things they will do with it.
A use scenario is a story or narrative—a thought experiment that is used to help you explore the set of tasks and interactions required for your design. A good use scenario does a number of things:
A persona (also known as an archetypal user) is an invented person that you use to represent a type of user in your use scenario. A persona can be based on a real person or on a set of real people. The idea is to make up personas to enable you to talk concretely about them as users of your system. For example, if I were designing a music purchase interface, I might create three personas:
Or, if I were designing an office information system, I might create three to five personas representing people in the office, such as the CFO, manager, administrative assistant, receptionist, and a visitor. It helps to give each persona a name and personality because you can then ask yourself how they might handle a situation or deal with a particular interface. They should be different from each other, so that they can represent the diverse range of people who might use your system.
Have fun and flesh them out! Sketch a picture of each persona and think about where they live and how they will access your system.
For more information about personas, see https://www.microsoft.com/en-us/research/wp-content/uploads/2017/01/personas-practice-and-theory.pdf and https://www.microsoft.com/en-us/research/wp-content/uploads/2017/01/PersonaBook.pdf.
The following is a single persona and use scenario for LeafView, a system that helps botanists identify plant species. This particular use scenario is rather involved and is a bit too specific about user interface elements such as buttons, but worked quite well for the project for which it was created.
Persona: Joe Brown is a 30 year old botanist that works at the Smithsonian Institution. He uses Microsoft Word in his daily work and a little bit of Excel, but isn't always comfortable using computers. He often carries a backpack and makes weekly trips to Plummers Island to collect and identify leaf samples. He wears glasses.
Use Scenario: Joe starts up LeafView and sees the browsing view, which enables him to look around at various plants. He knows he needs to start collecting today, so he closes the laptop and walks along the path looking for a specific plant. He sees what might be the right plant and cuts a leaf off the stalk, placing it on the gray background of the laptop. He snaps a picture and places the leaf in a sample bag. When he opens the laptop, he sees the acquired leaf image and can decide to search based on the image, save the image, or cancel. He searches for the leaf and the top 15 images are returned. He wants to see a comparison, so he brings the comparison image alongside the results. He zooms in on the Catalpa bignonioides species, and decides that this is the correct selection, after reading the text and looking at the veins and edges. He presses the select button and LeafView shows the information that will be saved. He clicks the save button and continues working.
It's really the process of creation that's important here. In creating personas and use scenarios, you're forced to think about the context and tasks of the design. Still, you'll want to walk through the use scenarios with your team, as a thought experiment, to see if you all agree on the use scenarios and to see if you might have missed something. Once you have personas and use scenarios, you can then start to design specific elements in your user interface, based on the requirements and interaction described in the use scenarios.
For further reading, you can check out: Using video to support interaction design.