|In the Alpha, it was adjustable with Attribute Points. In the Beta, Evasion raised with each level. It's hypothesized that the amount the stat increases with each level depends on the discipline being used. It is likely that certain Equipment will be able to increase and decrease a character's Evasion.
In Final Fantasy XI, evasion is a stat that is compared to an enemy attacker's accuracy to determine the chance that a character has of avoiding an attack. Evasion is directly affected by a character's evasion skill and AGI. For every two points of AGI a character has, their evasion is raised by one point.