An outer join preserves records even when the other list has no match. Left Outer keeps every row from the first query. Right Outer keeps every row from the second query. Full Outer keeps records from both sides. The direction depends on the two previews in the merge dialog, so read them before choosing the join kind.
A right join is useful when the roster is the complete population and you want to see drivers with no dispatch jobs. A full join is useful for reconciliation because it also exposes jobs with no roster entry. Expand the key from the right table as well as its descriptive fields. For a right-only record, the left key is null; the expanded right key tells you which record survived.
Outer joins don't remove duplicate matches. They also don't turn an unmatched value into zero or an empty string. Keep those nulls visible until you decide what they mean.