The application of appropriate Web site design and evaluation methods helps to ensure more usable and accessible Web sites. While in the literature guidelines and evaluation methods for accessibility and usability are given and discussed separately, we aim at identifying the relationships between these two concepts, in particular considering usability criteria for accessible Web sites. In this work, we propose a set of such criteria targeted to improving the navigability for a specific group of disabled users, i.e., vision-impaired people. The identification of the eighteen criteria suggested herein was performed through empirical feedback, by which potential issues were identified. Subsequently, a systematic method was developed on the basis of the analysis of potential solutions, resulting in a classification of the criteria according to usability aspects. Some example applications of the proposed criteria to three existing public administration Web sites are discussed.
User interfacesAccessibilityUsabilityGuidelinesVision impaired users