Smart Bidding chases every primary conversion action in the goals a campaign uses, and if those actions carry the same value, it can't tell the valuable one from the cheap one. Your campaign is set to optimize for conversions. The question nobody checks is: which ones, and does the bidding know which matter more?
How Google decides what to optimize for
Google is specific about this. For a campaign to bid toward a conversion action, two things must be true: the action is set as primary, and the campaign uses the conversion goal that contains it. Every action that meets both conditions steers the bidding. Secondary actions are still recorded, in the All conversions column, but they don't count for bidding unless you add them to a custom goal the campaign uses. The full definition is in our glossary entry on primary vs secondary conversion actions.
Two details make this easy to get wrong. Google groups actions into goals by category, so two actions in the same category travel together: a campaign using that goal optimizes toward both. And most accounts leave campaigns on the account-default goals, so every campaign inherits whatever is primary. Different categories don't protect you: if a signup goal and a demo goal are both account defaults, every new campaign bids toward both.
What it looks like in a real account
In one account we reviewed, a B2B SaaS was tracking two primary actions: account created and demo booked. Both used the setting that gives every conversion the same default value. Over the period we looked at, there were 90 account-created conversions worth a total of 90, and 7 demo bookings worth a total of 7.
To the bidding, a signup and a demo were the same thing. One point each. And signups are far easier to get than demos, so the system had every reason to find more signups and no reason to look for demos.
Fix 1: give the campaign one goalpost
We describe it on calls like basketball with two baskets and nobody telling you which one to shoot at. If you only want one action, make it the only primary action the campaign bids toward, and set the others to secondary. You lose no reporting: secondary actions still show in All conversions. You just stop paying the bidding to chase them. Google gives the same advice: if several goals track stages of one funnel, make only one of them the account default.
Expect a dip after the switch. Changing a campaign's conversion goals restarts Smart Bidding's learning phase, which Google puts at 7 to 14 days, so make the change once and leave it alone.
Pick that action carefully. Too far up the funnel, like a free trial anyone can start, and you get volume from people who will never pay. Too far down, like a closed deal three weeks later, and the campaign waits too long for a signal to learn from. We aim for the middle: the first action that reliably means a real prospect.
Fix 2: if several actions matter, make them worth different amounts
Sometimes you genuinely want both, with a preference. Then the actions need values that reflect what each is worth to you, and the campaign needs a strategy that reads values. Google draws the line clearly: Maximize conversions goes after the number of conversions, while Maximize conversion value goes after their total value. If a demo is worth ten signups to your business, value it that way and use value bidding.
The reverse mistake is also common. With a single conversion action that has the same value every time, Maximize conversion value has nothing to weigh, so it adds little over Maximize conversions. A single purchase action with real order values is different: that is exactly what value bidding is for. Value bidding earns its place when conversions are worth different amounts, whether that is several actions or one action with varying values.
The takeaways
- Smart Bidding optimizes toward every primary action in the goals a campaign uses, not just the one you care about.
- Two primary actions with the same value look identical to Maximize conversions, and the cheaper one wins.
- Want one outcome? Make it the only primary action; set the rest to secondary.
- Want several, ranked? Give them values that reflect their worth and use Maximize conversion value.
Common questions
Which conversion actions does Smart Bidding optimize toward?
Every action that is set as primary and sits in a conversion goal the campaign uses. Google requires both conditions. Secondary actions are still recorded in the All conversions column but are excluded from the Conversions column used for bidding, unless you add them to a custom goal the campaign uses.
What happens if two primary conversion actions have the same value?
With Maximize conversions, each one counts as one conversion, so the bidding has no reason to prefer the more valuable action. In practice it finds more of whichever is easier to get, which is usually the lighter, top-of-funnel action.
Should I use Maximize conversions or Maximize conversion value?
If one action matters, make it the only primary action and use Maximize conversions. If several actions matter but are worth different amounts, give each a value that reflects its worth and use Maximize conversion value. With one action at a fixed value, value bidding adds little; with real values that vary, like order totals, it is the right choice.
Why is my campaign optimizing for an action I didn't choose?
Google groups conversion actions into goals by category, and campaigns bid toward goals. If two actions share a category and are both primary, a campaign using that goal optimizes toward both. Actions in different categories end up together too when both goals are account defaults, which new campaigns use automatically. Move one action to secondary, or take its goal off the account defaults.
Do I lose reporting if I make an action secondary?
No. Secondary actions are still tracked and reported in the All conversions column. They just stop steering the bidding, unless you add them to a custom goal.