This measure is calculated according to the analytical section (i.e. Central Megaron Complex, Administrative Complex, Rowhouses West or Rowhouses East). The mean depth (MD) for a node is the average depth or average shortest distance from node n to all other nodes in the system. The MD is calculated by assigning a depth value to each space based on the number of steps needed to reach it from the carrier, then summing these values and dividing the sum by the number of spaces in the system, less one (to account for the original space).

Mathematically, the formula for MD is: MD(n) = TD(n)/(k-1) where TD = total depth and k = total number of spaces in the system.

These values describe the first use phase.