There are different ways to generate tests within Google Ads. Often, as with A/B testing ads, we simply edit a live campaign and see if the change had a positive or negative impact. However, Google Ads has a section called “Experiments” that is designed to create changes and then test those changes without actually changing the campaign. You’ll find it by clicking Campaigns > Campaigns > Experiments.
An experiment runs your proposed changes side by side with the original campaign, splitting traffic (and budget) between the two so you can compare performance directly. The original campaign acts as your control; the modified version is your variant. Both run in the same auction at the same time, which is what makes the comparison valid, rather than just looking at period-over-period data.
Setting one up
When you create an experiment, you’ll choose:
- Traffic/budget split – 50/50 is standard, though you can weight it if the original campaign is a strong performer and you don’t want to risk too much of its traffic
- Duration – Google typically recommends 4 to 6 weeks minimum to get a statistically significant read
- What you’re testing
From the Experiments page, you can pick from a few built-in test types:
- Custom experiment – full flexibility to change bidding, targeting, budget, or creative on a Search or Display campaign
- Performance Max experiment – tests a Performance Max campaign against an existing Standard Shopping campaign, letting you see if PMax would be better before actually changing it
- Optimize text ads – tests specific changes to search ad copy (find and replace, URL updates, or text swaps) across one or more campaigns
Once the test period ends, Google will tell you whether results are statistically significant. From there you can apply the winning changes to the original campaign, replace the original campaign entirely with the experiment, or end the test and move on.
Drafts
Drafts are a related feature for staging changes before you decide what to do with them. A draft is a copy of a campaign that lets you build out a set of edits (new bids, updated ad copy, restructured ad groups, and so on) without affecting the live version. Drafts are only available for Search and Display campaigns. You can’t create one for Shopping, Video, or App campaigns.
Use a draft when you want to review a complex set of changes first, then decide whether to apply them directly to the live campaign or spin them into a controlled experiment.
Ad variations
Ad variations is a separate tool for testing copy changes across multiple campaigns or an entire account at once, rather than one campaign at a time. It’s useful for something like testing a CTA change (“Buy now” vs. “Shop today”) across every ad it appears in, without setting up individual experiments for each campaign.
Why it matters
With Performance Max, Smart Bidding, and broad match handling more of the account automatically, manual control has decreased across the board. Experiments are the main way to validate whether an automated feature or campaign type is actually helping in your specific account, rather than just trusting Google’s recommendation.