Designing Highly Usable Web Applications

Web page (see Figure 36.2; b-3) representing the possible navigational targets (Tasks, Reports, and Contacts). However, as the label connected as, represented by the navigational link LI96 is a source link (empty arrow), the login information is showed in the same user’s generated home page (see Figure 36.2; b-3). The following usability metrics can be applied to the Navigational Model in Figure 36.2 (a):  Breadth of the inter-navigation (see Table 36.1): This metric can only be operationalized in those NADs that represent the first navigation level (i.e., inter-navigation). The calculation formula to be applied is: BiN (NAD) = Number of Output Target Links from Collections connected to Navigational targets. The thresholds 1 defined for the metric are: [BiN = 0]: critical usability problem; [1 ≤ BiN ≤ 9]: no usability problem; [10 ≤ BiN ≤ 14]: low usability problem; [15 ≤ BiN ≤ 19]: medium usability problem. Therefore, the breadth of the inter-navigation for the NAD shown in Figure 36.2 (a) is 4 since there are 4 first level navigational targets (i.e., Home, Tasks, Contacts and Reports). This signifies that no usability problem was detected.  Depth of the navigation (see Table 36.1): This metric considers the number of navigation steps from the longest navigation path. Therefore, the formula to be applied is: DN (NAD) = Number of navigation steps from the longest navigation path, where “Navigation step” is when a Target Link exists between two nodes and “Longest navigation path” is the path with the greatest number of navigation steps, which begins in the first Navigational Class or Collection where navigation starts, and which ends in the last Navigational Class or Service Link, from which it is not possible to reach another previously visited