User Interface Analysis and Design - Interface analysis and design models

User interface design begins with creating of different models of system function, human and computer tasks required to achieve system function are delineated, design issues applying to interface designs are considered, tools that are used and result that is evaluated by end-users for quality.

Analyzing and designing a user interface design requires four different models:
User Model
It is established by human or software engineer. It establishes the profile of end users of system. Users are categorized as:
- Novices: No syntactic and little semantic knowledge.
- Knowledgeable, intermittent users: Reasonable semantic and low recall or syntactic knowledge.
- Knowledgeable, frequent users: Good semantic and syntactic knowledge.

Design Model
Software engineer creates a design model. It includes data architectural, interface and procedural representations of the software.

User's Mental Model
It is created by end-user. It is the image of the system that end users carry in their mind. Accuracy of the description depends on the user's profile.

Implementation Model
It is created by implementers of the system. It combines the outward manifestation of computer based systems coupled with all information that describe system syntax and semantics.

When the implementation and user's mental model are coincident, users are comfortable with the software and use it effectively.