Measuring Navigational Burden

During the rapid growth of World Wide Web in the recent past, 'usability' and 'navigation' have emerged as problems of concern to the research community. Large Web systems are being made so complex that often the users have to make excessive amount of 'navigational efforts' to complete their tasks. This inflicts a heavy 'navigational burden' upon the users. Current collection of usability guidelines and principles has on the order of thousand rules to follow but none of them directly and specifically addresses the problem of 'navigational burden'. Thus there exists no tool/validator that can measure the 'navigational burden' a user experiences while performing some task on a Web site. Some usability and accessibility guidelines do exist which are validated by current tools just by analyzing the HTML pages, CSS (cascading style sheets) and other contents that can be retrieved from a Web site. However, the implementation of checks for these guidelines often suffers from the problem that no model is available, i.e. no abstract description of certain properties of the Web page (or its parts). This way, the validators either fail to find certain usability problems in the pages or it outputs too many general warning messages. For instance, it is straightforward to check given HTML code for the use of a limited number of different font faces, but it is not possible to do this reliably for measuring the 'navigational burden' a user experiences, unless a model or a mechanism provides information regarding the aspects that aggravate the 'navigational burden'. In this paper we identify certain aspects which aggravate the 'navigational burden' of users. We then present a mechanism how to measure 'navigational burden', followed by a discussion to integrate this mechanism into currently available automated usability validators