ΔE 12.6, fair: the same colour family, but not a straight swap. Transparent Ochre is more saturated than XV-88. They are different kinds of paint: Citadel XV-88 is an opaque base/layer paint and Green Stuff World Transparent Ochre 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 Ochre is more saturated than XV-88. They are different kinds of paint.
The same difference applies the other way round: XV-88 is 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 XV-88 on the colour wheel See Transparent Ochre on the colour wheel
All matches: XV-88 equivalents · Transparent Ochre equivalents