Attribution Modeling

Attribution modeling is the rule that determines how credit for a conversion gets split across the touchpoints (clicks) that led to it. If a customer clicks a Search ad, comes back a week later from social, returns again via email, then converts on a direct visit, which touchpoint gets the credit? That depends on the model.

Google Ads used to offer more attribution models (such as first click, linear, time decay, and more) but now just offers 2 models:

 Last click: Gives all credit for the conversion to the last-clicked ad and corresponding keyword.

 Data-driven: Uses your account’s own historical data to calculate how much each touchpoint actually contributed to a conversion, based on comparing paths that converted against similar paths that didn’t. It’s the default for every new conversion action.

Why DDA (Data-Driven Attribution) is the default

The average person clicks several Search ads before converting. Last click credits only the final one, which undervalues everything that built the path to that conversion. DDA solves this by using machine learning on your own account’s converting and non-converting paths to estimate each touchpoint’s real contribution rather than applying a fixed formula.

There used to be a minimum conversion volume required before DDA was available (roughly 600 conversions and 15,000 clicks a month). That threshold has been removed. DDA is now the default for essentially every new conversion action regardless of volume, though accounts with very low conversion counts should still check the results since a thin dataset can produce confident looking numbers that aren’t well supported.

When to still use last click

• Low-volume accounts where you want a transparent, easy-to-audit number rather than a model-driven estimate
• Diagnostics and baselines, comparing DDA against last click tells you how much credit is shifting toward assisting touchpoints and away from the closer
• Stakeholder simplicity, if a client wants a single clear rule they can explain without “the algorithm decided,” last click is the honest, simple answer

Checking the model on an account

To change a conversion action’s model: Go to Goals > Conversions > Summary, click the conversion action, select Edit settings, then Attribution model. Pick from the dropdown, save, done.

To compare models: Go to Goals > Measurement > Attribution, then Model comparison on the top page menu. Choose a dimension and use the Compare / With dropdowns to see how credit shifts between DDA and last click for the same keywords, ad groups, campaigns, or devices.