Mostly the number of edges in the dependency graph at the breakout point is used. For functions/methods, the number of possible execution paths (also known as Cyclomatic Complexity (CC)) is used.

Item type Example breakout Fat value
high-level package

("design level")

9 (edges)
package 6 (edges)
class 2 (edges)
method 2 (paths)

Example Fat derivation for each java item type