Google confirmed in July that first-click, linear, time-decay, and position-based attribution can no longer be selected in Google Ads. By September, any conversion action still running on one of those four models gets automatically migrated to data-driven attribution. There is no opt-out, no warning email, and no action required to trigger it — it happens on Google's schedule.
If you haven't looked at your attribution settings recently, you may not know which model you're on. That's the problem.
What's Getting Cut and What Remains
Only two attribution models survive: data-driven attribution (DDA) and last-click. Every rule-based model — first-click, linear, time-decay, position-based — is eliminated. Google cited adoption rates under 3% of conversions as the reason.
Data-driven attribution uses Google's machine learning to distribute conversion credit based on the actual influence each touchpoint had, calculated from your account's historical data. Unlike time-decay, which stacks most credit on the last few interactions before conversion, DDA attempts to measure the lift from each ad contact along the entire path.
Last-click is unchanged and still selectable. If you want complete control over where credit lands, you can switch any conversion action to last-click before September and that selection holds.
The Bidding Strategy Impact Nobody Is Talking About
Here's what matters most for your active campaigns: Smart Bidding — Target CPA, Target ROAS, Maximize Conversions, Maximize Conversion Value — reads your attribution data to make bid decisions. Attribution is the input. Change the input, change the output.
If your account was running time-decay attribution, Smart Bidding built its bidding model around signals that heavily weighted the final click in the conversion path. Move to DDA and that same bidding strategy now sees credit distributed more evenly across earlier touchpoints. The algorithm has to re-learn what a strong conversion signal looks like against the new distribution.
That recalibration isn't instant. Expect bidding variability and potential CPA movement in the weeks after migration. Google's own guidance: let Smart Bidding run for at least four to six weeks after an attribution model change before drawing conclusions from the data.
Check Your Accounts Right Now
Go to your Google Ads account. Tools → Conversions. Look at the Attribution model column for each conversion action.
If anything shows first-click, linear, time-decay, or position-based, Google will migrate it in September. The change happens in a batch across all affected conversion actions simultaneously — if you run multiple actions across multiple accounts, you'll see a synchronized data shift that can look like a campaign performance problem in your reporting.
This matters most for agencies managing multiple clients. A drop in October conversions that looks like a campaign issue may actually be an attribution interpretation issue. Know which it is before you're in a client call explaining a trend line.
Your Three Options Before September
Doing nothing is technically an option — it means Google picks DDA for you on its timeline.
Option one: let the migration happen. If your account generates more than 50 conversions per month, DDA should have enough data to model reliably. If you run Performance Max or broad match Search with Smart Bidding, DDA works with the same signals your bidding strategy already uses, so the alignment is logical.
Option two: migrate to DDA yourself now. Same outcome, but you control the timing. You set a performance baseline before the migration happens and avoid the September batch effect. You also get a head start on the recalibration period.
Option three: switch to last-click. If you manage lower-volume accounts — under 30 conversions per month — DDA may not generate reliable attribution anyway. Google says DDA "may default to last-click" for accounts below that threshold, which means the migration might change your model label without changing your actual measurement behavior. For high-confidence reporting on short purchase cycles, last-click is a deliberate choice, not a fallback.
One thing to verify: DDA doesn't model well with fewer than 30 conversions in a rolling 30-day window. If you're under that volume, confirm what your account actually does post-migration rather than assuming DDA is working.
September is six weeks away. Four attribution models are disappearing. Check your conversion action settings today so you're not reverse-engineering data anomalies in Q4.
