Global Navigation
http://www.webdesignpractices.com/navigation/globalnav.html

Adkisson, Heidi P.
Web Design Practices
2005

Abstract:

97% of sites included global links to the site's top-level categories. While global links to top-level categories help reinforce the breadth of a site's offering, they also consume significant screen real estate for links that arguably are not as relevant to users as page-specific content. This is particularly true at the lower levels of the hierarchy, where there is a larger amount of semantic distance between the global links and the page content.