Why was PD dropped?
The problems most often pointed out with PD: • Suppose that, in Third Edition, I have PD 4, Dodge 6 from whatever sources. If I don’t try to defend, I roll PD (4): 1.9%. If I dodge naked, I roll Dodge (6): 9.3%. If I dodge in PD, I roll against the sum (10): 50%. The probabilities would logically stack to more like 11%. “Greater than the sum of the parts” is one thing; more than four times the sum of the parts is another! Thus, PD baffled people who did the math. • Suppose that, in 3e, I have Dodge 6 naked. I stack on armor and shields, and get Heavy encumbrance – reducing my Dodge to 3 but picking up PD 7. Making myself half as mobile . . . I’ve increased by odds from 6 or less (9.3%) to 10 or less (50%). Again, no one disputes that the equipment should help some, or even a lot . . . but by a factor of five? Thus, PD baffled people who were trying to do heroic fiction where speed is effectively armor. • As for the argument about blows “bouncing off” armor, see them as simply blows fai
