L. Baresi, P. Fraternali, and G.-J. Houben (Eds.): ICWE 2007, LNCS 4607, pp. 370–384, 2007. © Springer-Verlag Berlin Heidelberg 2007 Considering Web Accessibility in Information Retrieval Systems Myriam Arrue and Markel Vigo University of the Basque Country, Informatika Fakultatea, Manuel Lardizabal 1, E-20018, Donostia, Spain {myriam,markel}@si.ehu.es Abstract. Search engines are the most common gateway for information searching in the WWW. Since Information Retrieval systems do not take web accessibility into account, results displayed are not useful for users with disabilities. We present a framework that includes the requirements to overcome this situation. It is composed of three modules: Content Analysis Module, Accessibility Analysis Module and Results Collector Module. This framework facilitates the implementation of search engines which return results ranked according to accessibility level as well as content relevance. Since criteria to sort results by their accessibility are necessary, we define accurate quantitative accessibility metrics which can be automatically calculated exploiting results yielded by any automatic evaluation tool. A prototype based on these requirements has been implemented to show the validity of the proposal. 1 Introduction The WWW has a great potential to make life easier for disabled people and make them less dependant on their relatives or friends since users can perform tasks they hardly could accomplish by themselves (i.e.: do shopping, buy tickets, etc.). However, as most websites are not accessible, these users come up against design barriers which do not let them access the information. In order to tackle this situation Web Content Accessibility Guidelines [7] were proposed by the Web Accessibility Initiative 1 (WAI). WCAG 1.0 guidelines define specific testing techniques or checkpoints which refer to accessibility issues in a more accurate way. Depending on the way a checkpoint impacts on the accessibility of a web page, each checkpoint has a priority assigned (1, 2 or 3 from more to less impact). In addition, based on these priorities three conformance levels are defined: • Conformance level A: all priority 1 checkpoints are satisfied. • Conformance level AA: all priority 1 and 2 checkpoints are satisfied. • Conformance level AAA: all priority 1, 2 and 3 checkpoints are satisfied. New versions of these guidelines are being currently developed. The last draft of WCAG second version was released in April 2006 [6] and proposes a new guideline 1 http://www.w3.org/wai