A recent client request to review their web site usability prompted me to codify some of the rules with which I approach web navigation. These 3 principles work 100% and every deviation from them only brings confusion to the end user and thus lowers the corporate ROI (Return on Investment).

Rule Number 3:

Mutual Exclusivity.

Make sure all your navigation bars and pages have mutually exclusive content, with two exceptions:

1) The footer links should mirror the header links since in long pages people lose track of the links they've seen earlier at the top of the page. It is a great relief to access the same or similar links at the bottom of a long page without having to scroll up to top.

2) When you have a page element that requires action on the part of your visitors and is crucial to your ROI, like a membership form, a product order button, repeating it on different pages is acceptable since some studies have shown that on the average it takes seven exposures before a visitor considers taking action on such an element.

Two major navigation blocks on a great majority of commercial web sites consist of 1) the vertical navigation links on the left sidebar or frame/pane of the page, and 2) horizontal navigation links, tabs (with or without drop-down menus)

The links in these navigation blocks should not be repeated in each other since it creates confusion and needless over-clicking. Anything that causes the user to expand extra energy for the same results would create psychic friction and frustration.

A good rule of thumb is to reserve the vertical navigation links (usually on the left side of the page) to the HOME link (should always be the first on top) and information links such as "Calendar of Events," "Careers," "Newsletter," "Map," or "Troubleshooting."

It is important to stick to the very same vertical links in every page to provide a solid perceptual anchor for the visitor. It's much easier for a visitor to feel "lost" if the vertical links keep shifting and changing.

The horizontal navigation links (usually placed on top of the page, right under the main header/graphics) should point at main sections or pages of the web site that can further serve as a mini-gateway to other related subordinate-level pages.

For example, for a Travel Agency web site, one of the horizontal/header links can take you to the "Bargains." Once you are in the Bargains page, a second set of dynamically-displayed horizontal links can point at individual travel bargain deals: "Disney," " Hawaii," "Miami," etc. without changing the vertical links.

Sticking with these 3 simple rules should solve 90% of all your navigation issues. Let me know how these principles work for you and I'd be happy to share your feedback with my other readers and clients.