Platform Bias
Platform bias arises because advertising platforms (Meta, Google) measure success using self-reported attribution models that systematically favor their own inventory. They see their own touchpoints clearly but are blind to others, leading to double-counting and inflated ROAS.
The Short Version
Grading your own homework. Every platform thinks it drove the sale.
Visual Explanation
What Is Incremental ROAS?
Your ROAS might look great. That doesn’t mean it worked.
Math That Doesn't Add Up
Meta claims 100 conversions. Google claims 80 conversions. You only had 120 total sales.
This 'overlapping credit' creates a false sense of security. You think you are profitable on both, but you are actually losing money on the portfolio.
How it works
Platforms use 'View-Through' windows to claim credit for anyone who saw an ad
They ignore the impact of other channels
They optimize to maximize their claimed number, not your bank account
Common Misconceptions
Trusting Dashboard ROAS implicitly
Summing up ROAS from all platforms (The math is impossible)
Ignoring the conflict of interest (Platforms sell ads *and* measure them)
Frequently Asked Questions
QAre the platforms lying?
Not maliciously, but their models are structurally biased to be optimistic. They measure 'Influence', not 'Causality'.
QHow much is the bias?
It varies. Retargeting campaigns on display/social can be inflated by 200-500%. Search is usually less inflated but still biased towards branded terms.