Google has a beta experiment that compares two sets of assets inside the same PMax asset group.
How it works:
The control group keeps your existing assets
The treatment group holds the alternatives, either new creatives or existing ones
You decide how traffic is split between the two
You pick a success metric such as conversions, value or clicks
Google's Experiment Guidance estimates how long the test needs to reach statistically significant results. Google recommends running it for at least 4 to 6 weeks.
This is a beta, so not every account may see it yet.
Spotted by Thomas Eccel.
