“Working with a product backlog does not mean that the Scrum team cannot create other helpful artifacts, including a summary of the various user roles, user story sequences to model workflows, diagrams to illustrate business rules, spreadsheets to capture complex calculations, user interface sketches, storyboards, user interface navigation diagrams, and user interface prototypes. These artifacts do not replace the product backlog but instead should elaborate and explain its content. And keep things simple. Only use artifacts that help the Scrum team move closer to a shippable product.”