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Examining the Order Effect of Website Navigation Menus With Eye Tracking

Alex J DeWitt

Journal of Usability Studies, Volume 6, Issue 1, November 2010, pp. 39 - 47

Article Contents


Results

A Spearman’s rank correlation test was conducted on the data to assess the relationship between the distance of a menu item (based on the above calculation) to its TTFF. The yielded p value was 0.178 showing little correlation. This implied that, for the menus tested, there was no significant impact of the distance of menu items from the centre of the menu on the time taken for users to direct their attention to them.

In practice, this means that users of websites were not consistently able to find menu items any quicker, regardless of whether they were at the start, middle, or end of the menu. This means that when designing a menu, less effort should be placed on the right position of items in the menu and more devoted to other factors that might include the terminology, taxonomy, and aesthetics, for example.

The results were cross examined to find any possible influencing factors.

Orientation of Menu

Three vertical menus were included in the study. Separate analysis of their data from the horizontal menus showed no significant effect on the TTFF from the distance of links from the centre of the menu (Spearman’s rank, vertical p = 0.505, horizontal p = 0.067). It must also be noted that one of the vertical menus was partially obscured by the page fold until users scrolled down; this would naturally increase the time taken to fixate on these menu items.

Practitioners should note that designing a vertical or horizontal menu does not seem to impact how quickly users can locate the desired item within the menus, although vertical menus run the risk of requiring page scrolling which does slow down navigation.

Size of Menu

The menus included in the study contained between 6 and 10 items; these were analysed separately and although they did show different patterns, none of them showed the expected pattern of TTFF increasing as distance from the centre of the menu decreases.

Most websites tend to have 6 to 10 primary navigation options, so the implications of this finding for website design are simply to state that designers should not panic that having a few more items will make it less efficient for users to find the one they want. For menus of more than 10 items, psychology research implies that users will have a harder time sifting through the information, but this is an area where a similar study could be performed in the future to assess performance on long menus.

Relevance of Menu Items on Task at Hand

Perhaps it is possible that users could more quickly recognise key words that are relevant to their current task; peripheral vision may be able to recognise familiar shapes or forms of words without directly placing the gaze on them or reading them. The eye-tracking technology does not record peripheral vision, only foveal vision, that is, the point on which the user is actively fixating. It was therefore interesting to classify menu items as to whether or not they were relevant to solving the task being completed at the time of eye tracking to see if there could be any impact of peripheral vision on helping users to spot relevant items more quickly.

Each menu item was classified as being either useful to the user’s task at the time the eye-tracking data was collected, or not (the path to the information requested in the task or what was thought to be the most direct path if there were multiple routes). The mean time to first fixation for items that were useful to the user was 10 s versus 11.8 s for items that were not useful, showing a slight increase in performance of locating useful items. However, when TTFF was plotted against the link’s distance to the centre of the menu, the expected decrease of TTFF with distance from the centre of the menu was not observed (Figure 2).

The Spearman’s rank correlation also showed no significant relationship in either case: p = 0.372 for items useful to the task and p = 0.154 for items not relevant to the task being completed. It must be noted that some users were able to complete their task without clicking on any menu items as relevant links were found elsewhere on the page, in which case fixations on the menu were coincidental to the task.

Figure 2

Figure 2. The time to first fixation varies with the distance (number of items) of menu items from the centre of the menu. Users were slightly faster at locating items that were relevant to their task, but there was no significant difference overall to items that were not related to the task at hand. Also, the error bars show a great variance of TTFF between each website menu.

Once again we did not see any significant impact of task relevance to TTFF; this was one possible explanation for why TTFF would vary that has been ruled out and forced us to consider other reasons why users would take longer to find the item they want. I suggest that this time was influenced by the aesthetics of the menu, including items around the menu which may draw attention; the user’s level of previous experience with other similar sites; and the users idiosyncratic search pattern. All of these are good topics for future research to help web designers make more effective menus.

Position of Item at Start or End of Menu

The primary aim of the study was to establish if a menu item’s distance from the middle affects the time it takes users to discover it, therefore top versus bottom positioning was outside the main scope. The initial formula described in the Method section of this paper does not differentiate between items located at the left and right sides of a horizontal menu or items at the top and bottom of a vertical menu. However such a discrimination was made by using the original formula and separating distances with a positive value (items at the start of a menu), with negative distances (items at the end of the menu). The average TTFF was then compared for each of these two groups.

It was found that items in the last half of the menu took 8 seconds longer to locate on average than those in the first half. However, the Spearman’s rank correlation did not show a significant relationship between the distance of the item from the centre of the menu and its TTFF for either items in the first half of the menu or the last half (p = 0.439 and p = 0.989, respectively).

Practitioners should note that there was no evidence in this study that more important items should go on the left and lead to progressively less important items on the right.

Other Measurements

The number of fixations before the target item was found was also considered. It may be the case that a long TTFF was produced by only a few fixations each of which lasted a long time or by very many shorter fixations. As shown in Figure 3, the mean average number of fixations before menu item acquisition varied from 10 to 40, but there was no pattern in items near the start of the menu taking more or less fixations to find. Once again, the error bars show a high degree of variability between each web menu in the number of fixations.

Figure 3

Figure 3. The average number of fixations before acquiring a menu item did not display a pattern when plotted against distance of the menu item from the centre of the menu. Error bars show the minimum and maximum number of fixations from the pool of web menus tested.

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