just as going from 98% effectiveness to 99% effectiveness halves your risk (you go from 2% chance of falling ill to 1%) its a common concept in games in which

just as going from 98% effectiveness to 99% effectiveness halves your risk (you go from 2% chance of falling ill to 1%) its a common concept in games in which armor follows a linear formula (each point of armor is more effective than the last when calculating effective health)