
I assume the skill of the roll relates to the skill of the NPC making the roll. The player has no skills and essentially makes no rolls.
There are many cards and the advisor that can be used before the player makes a decision to change the probability of success. Also, consider the skills of the NPC/Leader when selecting them for a job. Different circumstances may require different skills.
As pointed out by others, failed rolls still result in experience gained for the NPC leader (i.e. roller) with respect to the target skill.

