A discussion that I had recently concerning left or right justified navigation led me to research the subject a little. One of the most commonly cited sources of information on this is Kalbach and Bosenick’s study for Audi. Their findings show that left justified navigation faired slightly better in terms of pure performance but there was no real difference in terms of user perception and the group using right justified navigation took in more of the site content, hence the slightly slower test times.

My take on the subject is that the type of content and the site goals should factor into making the choice between left or right justified navigation.

We know from numerous studies that a web page has only a few seconds in which to engage the visitor’s attention. We also know from eyetracking studies that a visitor’s attention is focused primarily on the left hand side of the page. In the case of most commercial websites, the goal is to perform some sort of sales funcion – by this it could be selling a product or service or selling a corporate image or brand perception. The problem with using a left justified navigation on these sites is that during the 3 or 4 seconds in which you are trying to captivate the visitor, half of the screen area where they are most likely to be looking is filled with links to other pages. If you had 20 minutes to make a sales pitch on a product, would you spend the first ten minutes talking about other products? If you had a stand at a trade show, would you begin every conversation by pointing out other stands nearby?

The flip side of this is cases where a lot of heirarchical information needs to be presented. Conventions are well established in the presentation of the information hierarchy on the left. Tree views and multi level navigation menus are common enough in operating systems, applications and websites that there is little to no comprehension problems for visitors. A tree type navigation on the right hand side however feels strange and counter-intuitive.

It’s my opinion that site navigation carries less importance these days than it used to. A majority of web users arrive at an unfamiliar website via a search engine. In most cases they expect to arrive on the page most relevant to the term that they were searching for, full-site navigation is a secondary concern if you are already looking at the content which you required. Many sites containing large amounts of content have already realised this and concentrate on simplified navigation with a sophisticated on-site search engine and highlighting content that is currently popular or relevant.

Update: Maybe I’m on the right track here, Microsoft.com has just launched a redesign that features a right-justified navigation menu.