Resistance Resistance was a combat statistic that mitigated incoming magic damage and effects . Magic spells from the following five school s could be resisted from magical resistance : Fire , Frost , Arcane , Nature , and Shadow . There was no resistance stat for Holy , and as such no players nor NPCs could resist Holy spells . A character ' s current resistance score to each school was advertised on the character sheet . In PvE , resistance was highly situational and was typically only needed for certain boss encounters . The first one of this type was , famous for requiring significant fire resistance on all raid members . More recently , in Wrath of the Lich King , was made much easier with Frost resistance gear ( although this was not necessary ) . In PvP , resistance was helpful against spellcasters , although Resilience was generally considered to be a more useful stat when choosing between the two . In Mists of Pandaria . Spell resistance ( elemental and otherwise ) is being removed as a stat and mechanic in Mists of Pandaria according to Ghostcrawler ( Greg Street ) . Zarhym later explains that stats being sacrificed to add resistance which was only meaningful in narrow situations was a big part in removing this mechanic from the game . Effective Resistance and Average Mitigation . The effective resistance rating of the target was calculated as follows : In PvE boss fights , the player level was usually equal to or less than the boss level , and no spell penetration was in effect . Therefore , in this situation , it was safe to assume that the player ' s effective resistance was the same as the base resistance ( from the character sheet ) . Note that this formula rendered level 83 bosses as having 15 magical resistance against level 80 player attacks . The percentage of magical damage that was mitigated on average was calculated by the following equation ( note that this has changed in Wrath of the Lich King ) : For level 80 mobs this constant K was 400 . For level 83 boss mobs K was believed to be 510 . Binary Resist and Non - Binary Resist . Spell resistance was the second of two rolls to determine whether or not a spell was resisted . ( Spell hit was the first roll . ) The spell resistance roll would calculate in one of two different ways : one way for Binary Spell s , another way for non - Binary spells . Non - binary spells were spells which only dealt damage ( like or ) . Binary spells were spells which dealt a debuff ( like or ) or , for some other reason , needed to take full effect or no effect at all . For binary spells . Resistance reduced the chance for the binary spell to land by a certain percentage . Spell hit would not reduce this chance . It was assumed that this percentage was exactly the damage reduction percentage given above . For non - binary spells . Resistance increased the chance to suffer only a fraction of the spell ' s normal damage . As of Wrath of the Lich King , the possible percentages of damage resisted were weighted in sections of 0 % , 10 % , 20 % , . . . , 100 % averaging to the same overall damage mitigation . However only the closest three or four sections would ever occur at a given resistance value . This allowed a sufficiently high resistance to guarantee a certain resist percentage , even in the worst case . DoT spells were considered non - binary and the partial resistance calculation was applied on each tick . The probability of an x % resistance was given by the following formula ( AR is the average resistance calculated above ) : If the probability was less than 0 , it could not occur . In Cataclysm . Partial resists no longer occur against bosses . In Burning Crusade . In The Burning Crusade , the percent resisted had a chance to be 0 % , 25 % , 50 % , 75 % , or 100 % . The probabilities were weighted such that the average damage mitigated worked out to the same percentage as with binary spells . Sources of Resistance . Resistance could be obtained from buff s , potions , certain class talents , and gear . Racial abilities no longer granted magical resistance and instead granted a percentage chance to miss , as indicated by the table to the right . This chance to miss was added to the spell hit roll , and would not contribute to the non - binary damage mitigation . Stacking . The following list contains sources of resistance and stacking information . Each line will stack with other lines . In a group where Mark of the Wild , Aspect of the Wild , and Nature Resistance Totem is active , the group will only receive 130 Nature Resistance ( either from the aspect or totem ) . Effectiveness of Resistance . The damage absorbed per point of damage / healing / tanking stat lost decreased as resistance was gained , similar to armor . However guaranteeing a certain resistance percentage could be valuable , especially in fights with a large spike of elemental damage .