Smart Bidding
automated bidding / target CPA / target ROAS / auction-time bidding
Smart Bidding sets a bid for every individual auction rather than per keyword. Google calls this auction-time bidding and says some of its signals are exclusive to it. Microsoft is blunt about the trade: with auto-bidding you can only set a bid at campaign level, and the model computes the rest.
Google defines it narrowly enough to be useful. Smart Bidding refers to bidding strategies that use Google AI to optimize for conversions or conversion value in every auction, a feature it calls auction-time bidding. Target CPA, Target ROAS, Maximize conversions and Maximize conversion value are all Smart Bidding strategies, so if you are using any of those, this is what you have.
The real argument for it is in one clause about signals. Google describes signals as identifiable attributes about a person or their context at the time of a particular auction, and says they include attributes like device and location that are also available as manual bid adjustments, plus additional signals and signal combinations exclusive to Smart Bidding. Exclusive. There are inputs you cannot reach by adjusting bids yourself, at any level of effort.
Microsoft states the other side of that trade without softening it. When using the auto bidding function, you can only set the bid at the campaign level, and the auction bid for every keyword is calculated by the backend model in real time. Keyword-level bidding is not reduced. It is gone.
One more line from Microsoft changes how you read the result. Target CPA is a campaign-level target. Individual ad groups may have different costs per acquisition that vary over time while the campaign target is met, and different devices may see different costs too. The target describes an average across the campaign, not a promise about any part of it.
In practice
That average is where the surprises live. A campaign can sit exactly on its target while one ad group runs at double it and another subsidises the number. Nothing has gone wrong, and the strategy is doing what it was asked, but the account looks healthy at the level the target is set and uneven one level down. Looking at segments rather than the headline is the whole job.
Not the same as
- A maximum CPC bid
- That is a ceiling you set. Smart Bidding computes the bid for each auction and you set a target instead.
- Your budget
- The bid decides what you pay to enter an auction. The budget decides how much you spend in total.
Why it matters to you
It is proposed to almost everyone, usually as an upgrade, and it is more honestly a trade. You give up bidding at the keyword level and you gain signals that Google says are not otherwise available. Whether that trade pays depends on whether your conversion data is accurate, because a strategy optimising toward a conversion action that counts the wrong thing will do so very efficiently.
What to ask or check
- 01Which strategy are we actually on, and what target is set on it?
- 02Do the segments underneath the campaign target look like the campaign target?
- 03Is the conversion action this optimises toward the one that reflects real work won?
What people get wrong
That a target is a per-keyword promise. Microsoft says the target is set at campaign level, and that individual ad groups and devices may sit well away from it while the campaign meets it.
Red flags
- A target met at campaign level, with nobody having looked at the segments.
- A switch to automated bidding while the conversion action counts something other than real work won.
- Keyword-level bid changes proposed on a campaign where the platform says bids are computed by the model.
Where you will see it
In the bid strategy column of a campaign, and in every proposal to move an account off manual bidding.