ΔE 10.2, fair: the same colour family, but not a straight swap. Orange Brown is a little lighter than Raw Sienna.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 10). Orange Brown is a little lighter than Raw Sienna.
The same difference applies the other way round: Raw Sienna is a little darker.
ΔE is the colour difference between our two swatch estimates: under about 6 is close, over about 15 is loose. Real paints also differ in finish, coverage and how they thin, so test before you commit.
See Raw Sienna on the colour wheel See Orange Brown on the colour wheel
All matches: Raw Sienna equivalents · Orange Brown equivalents