The UCD approach focuses on systems development being driven by the user’s requirements instead of technical requirements. Design should depend on measures of how well the product has been used by highlighting user’s interaction and by making use of an iterative prototyping development process. When the methodology is applied to the user as the center of application; the users must be identified and analyzed by the user modeling. A user model has to be an integral part of any interactive system. A user model is different from both the actual knowledge possessed by a user and knowledge employed by system designers .
A. User Modeling
There are several modeling techniques: user roles, user segments, extreme characters , personas, etc. User roles and user segments are not particularly useful for developing user scenarios and for accommodating different users in a single project. Extreme characters is not a method that makes possible the characterization of real system users. By comparison, personas is a better modeling method based on the identification of characters who typify the system end user.
1) Creating Personas
Personas[3; 17] , introduced by Alan Cooper, are a technique of goal-directed design that is meant to help designers gain clarity and provide focus during the design process. They describe the goals and activities of archetypal users in a 1-2 page description based on a few ethnographic interviews with real users. Quesenberry states that, though the personas are traditionally created based on contact with real users – for instance, by interviews, contextual checking, and other qualitative means – the information that constitute the basis for personas can be collected by a team or a corporation.
The personas might be increased with details of true or imaginary stories. Personas are a design tool generally used within interaction design that help to give the interaction design team an idea of what a user may desire from a system . Personas are defined by their needs and goals. These include their personal goals as well as their goals for the system. A goal-directed design project may, and probably will, have multiple personas because different kinds of users with different goals will use the system. The system may not be designed for all personas. However, each system will have at least one primary persona. A primary persona is someone who must be satisfied with the system for it to be considered a success and who cannot be satisfied with an interaction designed for another persona.
The user interaction designed for each primary persona should be based on the needs and goals of that persona. Based on the type and the analysis for user research, there are two main methods to create persona: qualitative persona and quantitative persona. Qualitative research is the method that discovers new things from the small scale sample. The methods of qualitative persona research include: user interview, field investigation and usability testing. Through qualitative research, get the objectives, behavior and views of user. Quantitative research is the method that tests and proves certain things through a large number of samples. The methods of quantitative research include: questionnaire, log file analysis and user relationship management analysis and etc. The new way combined quantitative into qualitative is to create persona, which verifies and improves qualitative persona through quantitative methods. Through the quantitative research, verify the user groups divided by users’ quality. Persona is described with the goal, behavior, views, and the demographic characteristics.
2) Using Personas
Persona can clear the process which includes determining the functions and content of software and determining their priority. Persona plays an immeasurable role to make decision in advance. When determining the qualitative features and functionalities, persona can be used in brainstorming, to determine the priorities, to guide site structure, content and design. In brainstorming, discuss all the possible features, functionality and content based on the persona’s goals, views and behaviors. Through brainstorming, get a list of user functional requirements. By grading the each potential function with persona, it’s very easy to get scientific evaluation results that will be used to sort the all functions by their priority.