User blog comment:Fistful of Force/Fistful of Force's Tanking Guide/@comment-3360527-20110810032350/@comment-3360527-20110810051833

Wrong. The second one may be true in essense but it is situational and objective so it cannot be effectively argued where that point is at and is dependant on how geared AND skilled the other team is.

The first part, however, is just simply wrong. Your effective health points (EHP) gain is linear with armor (and MR). If you are at 30 armor OR 200 armor, you get the same EHP. Linear gains. The reason that there is the common misconception about 'diminishing returns' is because people see the % damage reduction and assume diminishing returns instead of looking at the math involved. I will give a few examples with simplified numbers and extreme cases to illustrate my point.

Starting at 0 armor and increasing to 1% damage reduction, your incoming damage goes from 100% to 99%. You net a 1% increase in damage reduction (99/100).

Being at 50% and going to 51% damage reduction, your incoming damage goes from 50% to 49%. This gives you a 2% increase in damage reduction (49/50).

Being at 80% and going to 81% damage reduction, your incoming damage goes from 20% to 19%. This gives you a 5% increase in damage reduction (19/20).

Being at 98% and going to 99% damage reduction, your incoming damage goes from 2% to 1%. This will net you a massive increase in your damage reduction by 50%.

All of the above are increased by 1% and yet each step up increases in value. This shows that for every bit of armor you have, the next bit of armor will become more valueable. In order to prevent this sliding scale and maintain a LINEAR progression for armor and MR, the % damage reduction has to have an exponential decrease in value. It is an understandably commom misconseption, but a misconception none the less.

TL;DR: Due to EHP, armor and MR are give linear gains. There are no diminishing returns.