This has been answered time and time again, but from my experience hn doesn’t ask this question sincerely - it’s usually just bait to argue with someone. Here i

This has been answered time and time again, but from my experience hn doesn’t ask this question sincerely - it’s usually just bait to argue with someone. Here is a thread where the question was addressed: https://news.ycombinator.com/item?id=36500138#36501923 https://news.ycombinator.com/item?id=36500138#36501923 But your guess is accurate, relevant section: > These campaigns have strictly enforced goals of return on ad spend (or sometimes net profit return on ad spend). When a new client starts running big budgets they run incremental alit y tests with their internal data science team, a neutral third party vendor (paid regardless of the outcome), and with the platform their spending money on. Each team shares their analysis but brands usually just ignore the platforms numbers. The advertiser can determine in their own, with legit statistical analysis, whether purchases would’ve occurred even if they hadn’t seen an ad.