When assigning jobs, in addition to the passion, one has to consider if they have traits which affect learning speed (fast learner, too smart). That way even if the colonist doesn't have a passion, the trait can compensate for it.

Having the hover tooltip show the final percentage would remove the step of going to the bio tab and checking the traits, which becomes annoying when there are 20+ colonists.

https://i.imgur.com/eV6KcgZ.png