Damage Reduction

Damage Reduction reduces incoming damage by a set percentage, stacking multiplicatively with other effects. It modifies the damage after it has been reduced by the relevant Damage Resistance stat

Overview
If a player has Dodgy 3 (-30%) and Lone Wanderer 3 (-20%) equipped, an incoming attack will be reduced by 44%. DMGf = DMGi * 0.70 * 0.80

Armor

 * Power armor passive (-7% per part, stacking additively)
 * Acrobat's armor (-50% per part, stacking additively) (Two parts = 100% reduction)
 * Assassin's armor (-8% per part, stacking additively)
 * Cavalier sprinting armor (-15% per part, stacking additively)
 * Cavalier blocking armor (-15% per part, stacking additively)
 * Exterminator's armor (-15% per part, stacking additively)
 * Ghoul slayer's armor (-15% per part, stacking additively)
 * Hunter's armor (-15% per part, stacking additively)
 * Mutant slayer's armor (-15% per part, stacking additively)
 * Troubleshooter's armor (-15% per part, stacking additively)
 * Sentinel armor (-15% per part, stacking additively)
 * Zealot's armor (-15% per part, stacking additively)

Perks and mutations

 * Dodgy (-10/20/30%)
 * Fireproof (-15/30/45% fire and explosion only)
 * Lone Wanderer (-10/15/20%)
 * Blocker (-15/30/45% melee only)
 * Empath mutation (-25% for teammates, +33% for player)

Magazines

 * Astoundingly Awesome Tales #8
 * Live & Love #9
 * Scouts' Life #1
 * Scouts' Life #2
 * Scouts' Life #7
 * Tesla Science Magazine #1
 * Tesla Science Magazine #2
 * U.S. Covert Operations Manual #3

Aid

 * Cola perk bubblegum
 * Nuka-Cola Vaccinated/Scorched/My Blood's In It (-15%)