ΔE 10.6, fair: the same colour family, but not a straight swap. Deathclaw Brown is more saturated than Earth. They are different kinds of paint: AMMO by Mig Earth is an ink, glaze or transparent paint and Citadel Deathclaw Brown is an opaque base/layer 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 11). Deathclaw Brown is more saturated than Earth. They are different kinds of paint.
The same difference applies the other way round: Earth 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 Earth on the colour wheel See Deathclaw Brown on the colour wheel
All matches: Earth equivalents · Deathclaw Brown equivalents