Accessibility or Usability of InteractSE? A Heuristic Based Approach to Evaluate Proposed Search Engine for the Visually Impaired Users.

Internet is the main source of information nowadays. The search engines must have various alternative manners for the search results representation. These representation methods will enable the end users especially the Visually Impaired VI web searchers to access the information on the web. The aim of this paper is design, evaluate and improve the interface for the VI users to perform search and browse results. This attempt provides a new accessibility tool for the VI web searchers. The conceptual modelling technique proposed in this paper is based on the Formal Concept Analysis FCA that hides the detailed information for the collected data results. This approach highlights the main discovered concepts to be focused on. That is combined with context interactive navigation, in an interface called Interactive Search Engine (InteractSE), which minimize the time and effort required by the VI users. There is no standardised set of guidelines or heuristics, which can be used for the evaluation of usability and accessibility aspects of such an interface. Therefore, interactSE was evaluated with experts using Nielsen heuristics and Web Content Accessibility Guidelines WCAG 2.0 in terms of both usability and accessibility. The analysis was carried out based on the number of usability problems identified and their average severity ratings. The results show that the most frequently violated heuristics from the Nielsen set are consistency and documentation. The average severity rating of all the problems found using Nielsen set is minor. The results also show that the most frequently violated WCAG 2.0 guidelines are distinguishable, followed by navigable and affordance. The average severity rating of all the problems found using WCAG 2.0 guidelines is also minor. The results show that Nielsen heuristics and WCAG 2.0 guidelines both contributed in identifying a number of usability problems.