Smart Bidding for retail
Automated bidding is not a black box you cannot reason about. It optimises a stated objective against a signal set, and most bad outcomes come from stating the wrong objective or changing it too often.
The strategies that matter for Shopping
| Strategy | Optimises for | Use when |
|---|---|---|
| Maximise clicks | Volume of clicks | Establishing data on a new account |
| Maximise conversions | Conversion count | Fixed budget, conversion value roughly uniform |
| Maximise conversion value | Revenue | Fixed budget, basket values vary |
| Target ROAS | Revenue at a return | Efficiency target matters more than volume |
| Target CPA | Cost per conversion | Uniform product value, cost ceiling per sale |
For most retailers with varied basket sizes, maximise conversion value with a target ROAS is the right end state. Getting there requires conversion value to actually be passed back correctly, which is the step accounts most often skip.
What the learning period is
A period after a significant change during which the strategy re-estimates. It is not a punishment and it is not fixed at seven days. It ends when the model has enough recent data under the new conditions. What it does mean is that results during it are not evidence.
Switching CSS does not trigger it. Campaign history, conversion data and learned patterns persist; the algorithm simply finds the auctions cheaper and adjusts within a few days.
What does reset learning
- Changing the bidding strategy itself.
- Large budget changes, roughly beyond 20 percent in one step.
- Changing the target ROAS or CPA materially.
- Restructuring campaigns or moving products between them.
- Changing conversion tracking or the value being reported.
The discipline
Change one thing, wait for it to be measurable, then change the next. That is unglamorous and it is most of the difference between accounts that compound and accounts that oscillate. It applies with particular force in the two weeks after a CSS switch, when a genuine efficiency gain is arriving on its own and any manual intervention will get the credit or the blame for it.