Recently I've been having a problem with some guild-mates who believe that resistances are based on a tiered system. I realize how the resist system works off a sort of chart, with resistances coming in chunks of 25%, but these gentlemen are arguing that resistances themselves are forced into a chart system and that there are essentially only 6 (or so) possible resist levels you can have.

I have argued that there's no reason to believe this, and that every point of resistance counts, but these guys are relatively sure of themselves despite not having any primary source. This problem is compounded by the fact that, at least from casual googling, there is no easily found site debunking or even verifying this.

So, I ask you, oh Jerks that are Elitist, how do resistances work? Can you please finally provide something I can link to that will end this arguing. At this point I wouldn't mind being proved wrong either.

http://www.worldofwarcraft.com/info/...sistances.html

...?

Have they ever resisted something when they have Mark of the Wild, and no other resist gear on? Because I know I have. Which means that resistances can't possibly be tiered, since at 0 resistance you resist 0% of all incoming spells.

I.E. they need to shut up with that 0-49, 50-99, etc. tier crap.

There are no tiers of resistance your resistance mitigation percent is simply:
min(0.75, (resistance_score/(enemy_level * 5))*0.75)

So 310 vs. a level 63 is 310/315 * 0.75 = ~73.8%
295 vs. a level 63 is 295/315 * 0.75 = ~70.2%

What the percentage means varies depending on whether or not the spell is binary (eg., cannot be partially resisted). If the spell is binary, the percent means how many attacks will be full resists. Otherwise, if the spell is partially-resistable, the percent tells you the average amount of mitigation you will see from the spells being cast on you.

Binary spells: Your chance to resist = (resistance / caster level) * 15%

If you have 180 SR and a level 60 casts Fear on you, you have a 45% chance to resist. If you have 181 SR, that's a 45.25% chance.

Damage spells: Average mitigation = (resistance / caster level) * 15%

Now, you can only get a 25%, 50%, 75%, or 100% resist. In that sense, it's tiered. But your effective mitigation is a continuous function, and every point of resist helps a little bit. As you move from 200 resist to 250 resist, you will see fewer 25% resists and more 75% resists, increasing your average mitigation accordingly, for example.

Both are capped at 75%.