Problem addressed
Evaluating and collect accessibility status of
large sets of Web sites:
• according to different guidelines (e.g. WCAG
2.0)
• periodically and automatically
• summarizing results, thereby offering an
effective and feasible view of the impact of
accessibility barriers measured on a large
scale sample of Web sites
1
Strategy
• We designed and implemented AMA,
(Accessibility Monitoring Application) to
evaluate and collect accessibility status of
large sets of Web sites
• We defined the BIF (Barriers Impact Factor)
metrics, to summarize results collected by
AMA,so as to quantify:
– each accessibility error in terms of how it affects
user's browsing by means of assistive
technologies
2
Strategy (2)
The BIF metrics is computed as follows:
BIF(i) = Σerror #error(i) x weight(i)
– The lowest value of BIF could be 0 (absence of barriers).
– The higher is the BIF value and the higher is the impact of a certain barrier on
a specific type of assistive technology/disability.
– Barriers have been grouped into 7 sets, per assistive technologies and per
disabilities:
• screen reader/blindness, screen magnifier/low vision, color blindness, input device
independence/movement impairments, deafness, cognitive disabilities,
photosensitive epilepsy.
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BIF on AMA
• AMA shows also evaluation results based on
aBIF (the average barriers impact factor on the
whole set of barriers)
• Weights are set as:
• the weight of each error which requires a
manual control is 0
• the weight of any level AAA error is 1
• the weight of any level AA error is 2
• the weight of any level A error is 3
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