Target CPA, Maximise Conversions and tROAS are genuinely powerful. But they're prediction engines, and a prediction engine is only as good as the examples it learns from. Feed it bad conversion data and it optimises confidently toward the wrong outcome.
Smart bidding is only as smart as its data
When you hand Google's bidding a conversion, you're teaching it "this is what good looks like, find me more." If your conversions are misfiring, double counting or counting low value actions, the model learns the wrong lesson and spends accordingly.
The failure modes to watch for
- Not firing, a broken tag or a redirect means conversions never register, and bidding starves.
- Double counting, 'every' vs 'one' counting, or duplicate tags, inflate results and mislead the model.
- Counting the wrong thing, a newsletter signup and a $5,000 sale are not the same conversion.
- No value, without conversion values, tROAS has nothing to optimise toward.
Get the value right, not just the count
If different conversions are worth different amounts, tell Google. Values based bidding lets the system chase revenue, not just volume, but only when you've configured conversion values honestly.
A quick sanity check
Do your Google Ads conversions roughly reconcile with what the business actually sees in leads or sales? If the numbers are wildly off in either direction, fix tracking before you touch a single bid. It's the least glamorous work in the account and the highest leverage.