GUIDe – Implementation phase
The user interface specification produced in the GUIDe model sets requirements for designing the implementation, but the GUIDe model does not specify a process for the implementation phase. The implementation phase may be based on the waterfall model (shown in the figure) or the Extreme Programming (XP) model, for example, depending on what is most optimal for e.g. the deployment schedule, programmers’ professional expertise, or the financing of the project. With the help of the validated and tested user interface specification, we have already attempted to minimize the risks that relate to the user interface, data requirements and functionality.
The user interface specification is the key tool at the implementation phase. In addition to using it to create the data model or the UML use cases for implementation, we can prioritize the features with it. The implementation can be divided into milestones, whose results can be verified against the user interface specification, among others.
Although the user interface specification is made in the beginning of the project, some user interface designs typically require some compromises as the implementation design and coding progress. For example, it may be too difficult to implement some of the designs that are excellent for the user with the available tools. As a result, it may be worthwhile to lower the usability of these designs a little to achieve savings in implementation. The compromises should be made by the user interface designers, so that the programmers do not need to create interaction design, which they are typically not proficient in. The user interface designers are able to optimize the compromise designs so that they are as good as possible from the user’s point of view.