Measurement & Tracking
Data-Driven Attribution (DDA)
Data-driven attribution is Google's model that assigns conversion credit across ad interactions using machine learning on your account's actual conversion paths, rather than a fixed rule like last click.
In practice
DDA compares the paths of users who converted to those who did not and estimates how much each interaction, keyword, and ad changed the probability of conversion. A generic search that appears early in many converting paths earns more credit than last click would give it; a brand click at the end earns less.
It is now the default model for new conversion actions in Google Ads and works across Search, Shopping, YouTube, Display, and Discovery interactions. It no longer has the strict minimum data thresholds it launched with, though its estimates are more reliable with more conversions.
What DDA does not do is see interactions outside Google. A Meta click that started the journey is invisible to it. That is why MER and holdout tests remain necessary for cross-platform budget decisions, and why the shift to DDA should be treated as a reporting change to be explained, not as a discovery that upper-funnel campaigns suddenly work.
Why it matters
It is the default lens through which Google Ads now reports and optimizes, so its logic shapes every decision the algorithm makes.
RELATED TERMS
Attribution Model
An attribution model is the rule set that decides how credit for a conversion is divided among the ad interactions that preceded it, such as last click, first click, or data-driven.
MER (Marketing Efficiency Ratio)
Marketing efficiency ratio is total business revenue divided by total marketing spend across all channels, measured without platform attribution.
Smart Bidding
Smart Bidding is Google's set of automated, conversion-based bid strategies (Target CPA, Target ROAS, Maximize Conversions, Maximize Conversion Value) that set auction-time bids using machine learning signals.
Written by Ilya Bulychev, Founder, Live PPC Ads. Part of the PPC Glossary.
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