Assessing the Effort of Repairing the Accessibility of Web SitesPresentation Transcript
ASSESSING THE EFFORT OF REPAIRING THEACCESSIBILITY OF WEB SITES Nádia Fernandes, Luís Carriço University of Lisbon ICCHP, Linz, Austria, July 11-13, 2012
ICCHP, Linz, Austria, July 13, 2012 2
ICCHP, Linz, Austria, July 13, 2012 3Introduction• 40-50% of the Web content uses templates.• Evaluations are performed in pages as a whole.• Obfuscating results.• Available metrics may be misleading.
ICCHP, Linz, Austria, July 13, 2012 4Objectives1. Assess the effort of repairing a site’s accessibility that was originally developed using templates Requirements: • Develop a new metric, • Template detection algorithm2. Introducing accessible templates as a form of rapidly repairing a page
ICCHP, Linz, Austria, July 13, 2012 5The Accessibility Repairing Effort Metric (AREM) The metric considers the sum of the number of fails and warnings reported by accessibility evaluation techniques, excluding repeated instances.“Primitive elements”- elements of a page, when an element thatis part of a template is only considered once.
ICCHP, Linz, Austria, July 13, 2012 6The Accessibility Repairing Effort Metric (AREM)The purpose of this metric is:1. assess the quality measurement of the accessibility of site construction (effort person.month);2. and not the perceived quality of the site towards end-users.
ICCHP, Linz, Austria, July 13, 2012 7The Platform for Accessibility EvaluationBasis: • QualWeb evaluator • Fast Match algorithm
ICCHP, Linz, Austria, July 13, 2012 8Procedure1. The DOM trees are obtained2. The pages are compared using the Fast Match algorithm • Comparative function • Result: The “primitive” nodes3. The accessibility evaluation is executed (QualWeb evaluator)4. Reports generation (new reports)5. The repairing effort estimation according to AREM is computed.
ICCHP, Linz, Austria, July 13, 2012 9Experimental Study• Objective: understand the advantage of using AREM and validate the template detection method.• Object of study: 15 sites with templates (Alexa Top 100) 5 high 5 low level level 5 medium level
ICCHP, Linz, Austria, July 13, 2012 10Experimental Study• QualWeb was applied with the template aware option set.• The values for the AREM using the element primitiveness.• We used a conservative rate metric to obtain values of accessibility quality to compare with AREM. rate conservative =
ICCHP, Linz, Austria, July 13, 2012 16Validating the Approach % errors on template Web sites % template detectionHigher level of 56% 14%template detection 51% 8%Mid level of template 33% 6%detection 31% 12%Lower level of 18% 7%template detection 15% 1% The number of incorrect elements detected by Fast Match algorithm is less than 10% (average).
ICCHP, Linz, Austria, July 13, 2012 17Discussion• The validation of the template detection yielded a deviation.• The algorithm had more failures in sites which use more template based components.• Regarding the AREM metric: • The difference between the computed values is high; • Less 30% of repairing issues (primitive elements); • Depending on the sites this value can decrease substantially.• These results confirm and support our previous experiment’s results.
ICCHP, Linz, Austria, July 13, 2012 18Conclusion• Templates can be very important, reducing the effort of correction.• The metric defined is a real indicator of the work that have to be done, unlike certain quality metric that can be misleading.• We performed a validation experiment of both metric and framework and conclude that the template detection algorithm has a high efficacy.
ICCHP, Linz, Austria, July 13, 2012 19Future Work1. Improvements of Fast-Match algorithm to guarantee a higher accuracy level;2. A large-scale evaluation of the fast match algorithm.
ICCHP, Linz, Austria, July 13, 2012 20Thank email@example.com