Quality Assessment

Abstract

Quality is a relevant factor for the success of Web applications. In the last few years, it has received great attention, being recognized as a fundamental property for acceptability by users of Web applications. Defining methods for assessing quality is therefore one of the goals of Web engineering research. Also, much attention to quality is paid by the industry: some studies and best practices have in fact demonstrated that adopting methods for quality assessment during the whole development process enables cost saving, with a high cost-benefit ratio, since they reduce the need for changes after application delivery [Mad99, NL93, JBR99, Con02, LC02].

In order to achieve high-quality applications, it is necessary to address quality issues explicitly, by adopting appropriate techniques spanning the entire application life cycle [JBR99, Con02]. The practice of adopting quality assessment methods at any stage of the development process, by evaluating quality of incremental design artifacts, as well as of the final product, is therefore increasingly receiving consensus. This has resulted in the proposal of the so-called iterative design [Som96, Con02]. With respect to more traditional models suggesting a top-down, analytic approach (as, for example, the traditional waterfall model), iterative design proposes the development process be complemented by a bottom-up, synthetic approach, in which the requirements, the design, and the product gradually evolve, becoming well defined step by step. The essence of iterative design is that the only way to ensure the effectiveness of some design decisions is to build and evaluate them, through the use of application prototypes. The application design can be then modified to correct any false assumptions detected during evaluation, or to accommodate newly emerged requirements; the cycle of design, evaluation, and redesign must be repeated as often as necessary.