Why Testing Should Always Start with ABO

One of the biggest debates in Meta Ads is whether to start with ABO (Ad Set Budget Optimization) or CBO (Campaign Budget Optimization). Many advertisers rush straight into CBO because it feels easier — let Meta’s algorithm decide where to spend the money. But here’s the truth: when it comes to testing, ABO should always be your starting point.

ABO gives you more control, cleaner data, and better clarity about what’s actually working. Without it, you risk wasting budget on uneven spending and never really knowing which audience or creative was the true winner.

1. What Is ABO vs. CBO?

1. ABO (Ad Set Budget Optimization): You assign budgets at the ad set level, giving each audience a fixed spend.
2. CBO (Campaign Budget Optimization): You assign one budget at the campaign level, and Meta distributes it across ad sets.

2. Why ABO Is Better for Testing

a. Equal Budget Distribution

Each ad set gets its own budget, ensuring fair testing. In CBO, Meta may give 80% of spend to one ad set while ignoring others.

b. Cleaner Data

Since every audience and creative has equal spend, you can accurately measure performance and identify winners.

c. Faster Learning

ABO removes the bias of algorithm favoritism, allowing you to test multiple variables without Meta “picking favorites” too soon.

d. Better Control

You can pause or scale specific ad sets independently. CBO doesn’t give you the same level of control during testing.

3. When to Use ABO

1. Testing Audiences: Different interests, lookalikes, or geographies.
2. Testing Creatives: Multiple hooks, formats, or messaging angles.
3. Small Budgets: Prevents Meta from wasting all spend on one random ad set.
4. Early Stage Campaigns: When you don’t know what works yet.

4. When to Switch to CBO

Once you identify winning audiences and creatives through ABO, you can combine them into a CBO campaign. CBO is powerful for scaling because it allocates more budget to proven winners automatically.

5. Real Example

A D2C clothing brand tested 4 audiences using CBO with ₹2,000/day. Meta spent 70% of the budget on one audience, ignoring the others. They never knew if the other audiences could have performed better.

Later, they switched to ABO, giving ₹500/day to each audience. Two hidden winners emerged, and overall CPA dropped by 32%.

6. Common Mistakes to Avoid

1. Jumping straight into CBO without testing audiences.
2. Giving ABO ad sets very low budgets (can’t exit learning).
3. Not excluding overlapping audiences in ABO testing.
4. Keeping ABO on forever without moving winners into CBO for scaling.

7. Pro Tips for Testing with ABO

1. Use 3–5 ad sets at a time for cleaner data.
2. Keep budgets consistent across ad sets.
3. Run tests for at least 3–5 days before deciding winners.
4. Move winning ad sets into CBO campaigns for scaling.
5. Always document results in a testing sheet for future use.

Testing with ABO ensures you get accurate, unbiased results that guide better decisions. Once you know your winning audiences and creatives, you can confidently scale with CBO. This structured approach saves money, speeds up learning, and improves long-term performance.

At AlmostZero, we help businesses build smart testing frameworks with ABO and scale efficiently with CBO.

Want to stop guessing and start testing the right way? Partner with AlmostZero and let’s design your ABO-to-CBO growth strategy.