I got a call this morning from a business owner who is going to become a new client of mine. They were worried about their Google Ads account because all of a sudden it just stopped working. This campaign had been his primary source of leads for months and had suddenly just stopped working. Barely any impressions and clicks, conversions way down, etc. And on the business side of things, the phone stopped ringing and lead forms stopped coming in.
When I looked under the hood, I saw the culprit immediately. Their former manager had gone into the settings and recklessly flipped the bidding strategy to Target Return on Ad Spend (tROAS).
Changing your bidding strategy recklessly when a campaign is already performing strongly is about the dumbest thing you can do. It’s like being in a plane at 30,000 feet and deciding you want to swap out the engine just to see if you can go five miles an hour faster. You’re gambling with the entire aircraft.
The Illusion of Control vs AI Reality
Google Ads is no longer a simple calculator; it’s a living, breathing AI organism.
According to Google Ads Support, Smart Bidding uses “auction-time bidding,” which leverages millions of signals to determine the likelihood of a conversion. When you run Maximize Conversions, you are “training” the system. You’ve given it data. It knows what a lead looks like.
When you suddenly flip to tROAS without the proper data foundation, you aren’t “optimizing”—you are starving the AI.
Here’s what probably happened. Max conversions was probably working great. And someone changed it to target ROAS bidding. I have used target ROAS sometimes and have nothing against it. But on a lead gen campaign, if you don’t have values in the conversions that make sense, you can get yourself in trouble. If they had default values of $1 and the cost per click was $20 and the cost per conversion was $100, the system won’t be able to get a 500% of whatever ROAS and it’ll clam up and shut down volume since it can’t achieve it’s goal.
But if you recklessly switch to Target ROAS without assigning specific dollar values to your leads, or you set a target that is mathematically impossible based on your history, the AI gets confused. It sees your “5:1 return” requirement, and it realizes it can’t get that outcome.
So, it does the only safe thing it can do: It stops bidding. The campaign “clams up.” In an attempt to force certainty, you’ve created a total shutdown.
And that’s what happened to my new client. The system saw that it couldn’t get the required ROAS it had been instructed to get, and it shut down basically. That’s why volume dropped off.
Testing new bidding strategies is fine, but they should have used an experiment.
The “Safe Bet” Strategy: Use Experiments
If you want to move to a new bidding strategy, you don’t just “flip the switch.” You have to use Campaign Experiments. This is the only way to maintain certainty while seeking improvement.
Here is how you do it the right way:
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The Split: Take your successful campaign and create an experiment.
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The Control: Keep 50% of your traffic on the original bidding strategy. This keeps the lights on and the leads coming in.
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The Test: Run the other 50% on the new strategy (like tROAS).
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The Verdict: Wait for a statistically significant amount of data.
By using an experiment, you protect your business. If the new strategy fails, it only affects a portion of your traffic. Your control campaign stays healthy. But beyond that, the control campaign stays totally in place and to get back to it fully, you can just simply end the experiment.
That’s the beauty of experiments. If they don’t work, you just end them, and they don’t affect the original campaign.
Be Careful With Conversions and Bidding Strategies
As a business owner, your job is to protect your conversion tracking system and your bidding strategy.
Google Ads can work amazing when great conversion tracking is in place and you feed that data to max conversion bidding. But if you break you conversion tracking, you’re in trouble.
Equally important is protecting your bidding strategy. Once you have a bidding strategy that works, protect it! Stick with it!
You should never just change a bidding strategy that is working. You can try to improve, that’s fine, but use an experiment!
The Rothman PPC Takeaway – Bidding strategies can make or break a Google Ads campaign. Don’t change them recklessly. Always use an experiment.
