Full Answer

Data quality determines ROAS because ad algorithms are only as good as the conversion signals they receive. Meta requires an Event Match Quality score of 8.5/10 or higher to unlock advanced optimization features like Advantage+ campaigns. The practical difference is significant: a store capturing 95% of conversions versus one capturing 65% sees 15-30% better ROAS because the algorithm has more accurate training data. Server-side tracking with customer matching (hashed email, phone) consistently achieves the highest data quality scores.