Web site evaluation methodologies and validation engines take the
view that all accessibility guidelines must be met to gain compli-
ance. Problems exist in this regard as contradictions within the
rule set may arise, and the type of impairment or its severity is not
isolated. The Barrier Walkthrough (BW) method goes someway
to addressing these issues by enabling barrier types derived from
guidelines to be applied to different user categories such as motor
or hearing impairment, etc. In this paper, we use set theory to cre-
ate a validation scheme for older users by combining barrier types
specific to motor impaired and low vision users, thereby creating a
new “older users” category from the results of this set addition. To
evaluate this approach, we have conducted a BW study with four
pages, 19 expert and 49 non-expert judges. This study shows that
the BW generates reliable data for the proposed aggregated user
category and shows how experts and non-experts evaluate pages
differently. The study also highlights a limitation of the BW by
showing that a better aggregated user category would have been
created by having a severity level of disability for different impair-
ment types. By extending the BW with these impairment levels, we
argue that the BW would become more useful for validating Web
pages when dealing with users which multiple disabilities and thus
we would be able to create a “Personalised Validation and Repair”
method.
