ΔE 13.3, fair: the same colour family, but not a straight swap. Transparent Yellow Iron Oxide is a little darker, much more saturated than Imp Yellow. They are different kinds of paint: Army Painter Imp Yellow is an opaque base/layer paint and Golden Transparent Yellow Iron Oxide is an ink, glaze or transparent paint, so they won’t behave the same on the model even where the colour is close.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 13). Transparent Yellow Iron Oxide is a little darker, much more saturated than Imp Yellow. They are different kinds of paint.
The same difference applies the other way round: Imp Yellow is a little lighter, much more muted.
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 Imp Yellow on the colour wheel See Transparent Yellow Iron Oxide on the colour wheel
All matches: Imp Yellow equivalents · Transparent Yellow Iron Oxide equivalents