In-platform ROAS vs incrementality — which to scale on

In-platform ROAS vs incrementality — which to scale on

Scaling on the numbers Meta shows you? Careful which numbers:

— In-platform ROAS (Meta's own attribution): fast, available, fine for relative comparisons between ad sets in the same account.
— Incrementality (would this sale have happened anyway?): the truth, but slow — needs holdout tests or geo-lift studies to measure real lift.

When each is enough:
— Comparing two ad sets, same conditions → in-platform's fine, the bias is roughly equal across both.
— Deciding whether to scale total spend or trust retargeting's ROAS → you NEED incrementality, or you'll scale phantom credit.

Risk: Meta over-claims conversions, especially on retargeting and ASC. Scaling on in-platform alone inflates your confidence.

Run ONE holdout test before you bet a big budget increase on Meta's reported ROAS.