Damage Threshold

Damage Threshold is a combat statistic in Fallout, Fallout 2, and Fallout Tactics: Brotherhood of Steel. It was removed in Fallout 3, leaving Damage Resistance as the only armor statistic. However, it was restored in Fallout: New Vegas.

Fallout: New Vegas
(DT) is a derived static value that is directly subtracted from the damage of each shot taken. In simple terms if a shot is fired with a damage value of 20 and the targets DT value being 15, then 15 points of damage will be removed from the shots damage. DT plays a integral part in combination with the targets Damage Resistance (DR) value to determine the amount of final damage inflicted upon the target subject.

The combined statics of DT and DR (with DT being applied first) determines the total damage reduction applied to each shot, however it should be noted that it is not a simple issue of just subtracting the defined value from the damage of each shot, damage negated in this way will never be reduced below 20% of the weapon's original damage regardless of both DT and DR.


 * $$\max((\text{Shot Damage} - \text{DT}) \times (100\%-\text{DR}\%), (\text{Shot Damage} \times20\%) \times (100\%-\text{DR}\%)) = \text{Damage Inflicted}$$

Damage which is reduced to below minimum value is indicated with a shield icon next to the health bar (either the PC, or the NPC's). When all of an enemy's DT (if it's not 0 to begin with) is overcome with Armor Piercing attacks, then a broken shield icon will be appear in its place instead. The shield icon is shown during V.A.T.S and on the HUD's health bars once damage has been inflicted upon a target and will remain for 3 seconds afterwards.

The default value for DT is set at 0, this is then modified mainly by the DT value of Armour and Clothing worn. Other attributes that can also effect the DT value both permanently or temporary of a character are Perks, Traits, Consumables and Ammunition.

Bugs
In spite of DT being the determining factor for armor in New Vegas merchants when repairing armor will list DR instead. All armors when viewed from the repair screen have a DR of 0 NOTE: Fixed with patch 1.1.1