class A{}
class A1 extends A{} // 1 depth
class A11 extends A1{} // 2 depth
class A12 extends A1{} // 2 depth
class B{}
class B1 extends B{} // 1 depth
class C{}
class D{}
There are 4 root class A, B, C, D
- A hierarchy has 2 depth
- B hierarchy has 1 depth
- C hierarchy has 0 depth
- D hierarchy has 0 depth
Sum of it is 3.
AHH = 3/4 = 0.75
From code
if (($count = count($this->rootClasses)) > 0) {
$this->ahh = array_sum($this->rootClasses) / $count;
To reduce this score you could add more root classes without children at all(or lower than the deepest). Or reduce depth of hierarchy.