The Risks of Smart Bidding in Google Ads
Nov 03, 2025 Activating Smart Bidding in Google Ads is one of the biggest opportunities for growth—
but also one of the biggest risks.
If you don’t engage Smart Bidding at the right time or in the right way, it can completely derail your account performance.
In this article, we’ll break down the biggest misconceptions about Smart Bidding and how to use it safely and profitably.
The tCPA/tROAS Myth
One of the most common mistakes advertisers make is believing that the numbers in the Google Ads dashboard represent the full story of their business success.
Your conversion data inside Google Ads is important, but it doesn’t reflect your true business performance.
For example, I once posted a short video showing a campaign with a 200% ROAS.
The comments were full of people saying, “That’s not profitable!”
But what they didn’t know was that the business had a one-time product sale followed by an extended service plan, where the majority of profit came from repeat revenue.
When we began managing the account, we actually reduced their target ROAS to sell more upfront units—
because that drove more long-term profit.
The takeaway?
Do not judge your account’s success by how high your tROAS is or how low your tCPA looks in isolation.
Your tCPA and tROAS Are Brakes, Not Accelerators
Many advertisers mistakenly set their Target CPA or Target ROAS based on what they wish to achieve rather than what the data supports.
But these bidding targets act like brakes, not accelerators—they control volume, not velocity.
If your current CPA is $30 and your goal is $15, don’t set your Target CPA to $15 overnight.
Instead, lower it gradually to help Google’s algorithm adjust:
Example progression:
$30 → $25 → $20
Each adjustment should be spaced out over several weeks, allowing the algorithm to stabilize before the next change.
Monitor results every 60–90 days, not every few days. Frequent tweaks confuse the system and can cause performance drops.
👉The Google Ads Terms You Need to Know
When and How to Start Smart Bidding
Smart Bidding works best once your campaigns have consistent data and conversions.
Before activating it:
-
Ensure at least 30 conversions in 30 days per campaign
-
Verify conversion tracking accuracy
-
Use realistic starting goals (don’t over-optimize too soon)
Once enabled, evaluate performance over time, not in the first week. Google’s algorithm needs volume to learn and improve.
Real-World Smart Bidding Wins
Here are examples of how our clients have scaled with proper Smart Bidding strategies:
-
E-commerce client: lowered tROAS target to increase front-end sales and double customer lifetime value
-
Lead gen client: stepped down Target CPA over 60 days, maintaining volume while cutting cost per conversion by 40%
-
Service business: delayed Smart Bidding until reaching consistent conversion data, then used tROAS to scale profitably
Final Takeaway
Smart Bidding is powerful—but only when you respect the data behind it.
Treat tCPA and tROAS as tools for control, not shortcuts to profit.
Let your campaigns gather real-world signals, then use Smart Bidding to refine performance, not replace strategy.
FAQ
What is Smart Bidding in Google Ads?
Smart Bidding uses Google’s machine learning to automatically set bids that maximize conversions or conversion value based on your goals.
Why can Smart Bidding hurt performance?
When activated too early or with unrealistic targets, it limits data flow and can reduce reach and conversions.
What’s the difference between tCPA and tROAS?
tCPA optimizes for conversion volume within a target cost per acquisition; tROAS optimizes for conversion value relative to ad spend.
When should I switch to Smart Bidding?
Once your campaign consistently generates at least 30 conversions in 30 days with stable tracking and data accuracy.
How often should I adjust bidding targets?
Every 60–90 days. Frequent changes reset learning and can hurt algorithm performance.