One point in spell damroll is equal to 1% gained in spell damage.
Spell damroll is capped at 40.
Spell damroll does not affect damage over time spells.
Spell damroll begins at 0.
Spell damroll increases by 1 point for every 2 points of Mind over 52.
Spell damroll increases based on bonuses from worn equipment.
Spell damroll increases based on bonuses from spells and skills.