Effective health

Effective health (EH) is the practical health of a unit after attack and defense modifiers are considered. It may be calculated as follows:

$EH=h_{init}\times \left ( \frac{d_{init}}{d_{mod}} \right )$

where:

• h_init is the unit's health before attack and defense modifiers are applied
• d_init is the attack's damage before attack and defense modifiers are applied
• d_mod is the attack's damage after attack and defense modifiers are applied

Or in English: Effective health is (old health) times (old damage) divided by (new damage).

d_mod is the determinate. Attack bonuses increase d_mod and decrease effective health. Attack penalties, such as defensive armor, decrease d_mod and increases effective health.

Effective health may be expressed as a percentage of base health:

$P=\frac{EH}{h_{init}}$

Or in English: % is (effective health) divided by (old health).

Damage Modifiers in StarCraft II

In StarCraft II, d_mod is calculated by factoring in the following attributes in the given order:

1. Attacker damage tech upgrades.
2. Defender shield tech upgrades, if shield strength is greater than 0.
3. Defender armor tech upgrades, if shield strength is 0 (as with all terran/zerg units, or protoss with shields down).
4. Hardened shields.
5. Guardian shield.