If you're using your digital marketing tools correctly you're already correcting for this. Instead of measuring how many people click on ads, measure how many

If you're using your digital marketing tools correctly you're already correcting for this. Instead of measuring how many people click on ads, measure how many people click on ads and then compare it to how many people click on organic results to the same query. Or run ablation experiments where you stop running the ads and see what that does to your clicks & conversions. If you were making $X + $Y with the ads and then you stop running them, hold everything constant (no new campaigns, no product changes, no seasonality), and you're suddenly making $X with organic traffic remaining constant, it's very likely that you're making $Y from your ads, particularly if $Y was directly attributable to ads-related sessions. If instead your organic traffic is now making $X + $Z, it's likely that your ads cannibalized $Z in organic spending and they are actually making $Y - $Z. Not saying all advertisers do this, but it's pretty basic data science. You should always have a control for every experiment you run.