The four different models that come into play when a user interface is analyzed for an application are the user model, task model, information model and interface model.
1. User Model: This model focuses on understanding the characteristics, needs, and behaviors of the application's target users. It involves creating user personas, conducting user research and considering factors such as demographics, preferences etc.
2. Task Model: The task model concentrates on defining the actions and workflows users will perform within the application. It involves creating use cases, user scenarios and flow diagrams to outline the steps users will take to accomplish their goals.
3. Information Model: This model deals with organizing and presenting the information within the application. It includes information architecture, content hierarchy, and data structures.
4. Interface Model: The interface model focuses on the visual and interactive aspects of the user interface. It encompasses layout design, navigation structures, visual elements and interactive components such as buttons and forms.