To normalize cage density metrics for rooms with different heights of racks, consider using the metric of "cages/shelf/room square foot" (developed by Jack Hessler and used for an NCI facility analysis) for your measure of room cage-density. This metric normalizes the standard cages per square foot for different rack heights in rooms. Thus, a density of 2.0 cages per square foot in a room containing 8-high racks, would be .25 cages/shelf/sq-ft (2.0/8), and a density of 2.0 cages per square foot in a room containing 10-high racks would be .2 cages/shelf/sq-ft.

- From Tradeline's Animal Research Facilities 2005 Conference