Strategy
Search advertising: which ad groups to split, merge, or retire
Which search ad groups to split, merge, or retire: use query overlap, conversion history, and target cost per acquisition to decide where budget goes.
What to take away
- Split an ad group when one theme inside it needs different ad copy, a different landing page, or a different bid target.
- Merge ad groups that chase the same intent with the same ad and the same page, because they only compete against each other.
- Retire an ad group when its theme cannot reach the target cost per acquisition after a fair test window.
- Decide with query overlap and conversion data, not with how tidy the keyword list looks.
Query overlap as the first structural test
Start with a search terms report covering 30 to 90 days. Group the terms by what the searcher wanted, not by the keyword that matched them. When two ad groups share many of the same converting queries, one of them is redundant. When a single ad group holds clearly different intents, the mismatched half will drag relevance down.
Keep the test cheap. Export the terms, tag each one by intent, and count how many appear in more than one ad group. The same report exists in Microsoft Advertising, and the same overlap test applies there.
Splitting an ad group: triggers and trade-offs
Split when a theme inside an ad group behaves differently from the rest. Common triggers are mixed intent, different profit margins, different compliance rules, or a landing page that fits only half the keywords.
Split, cap, or retire?
Two intents inside one ad group?
Split by intent
Keep structure
Splitting an ad group
| Signal | Structural move | What changes |
|---|---|---|
| Two intents inside one ad group | Split by intent | Ads, pages, negatives |
| One keyword takes most of the spend | Split it out or cap it | Budget control |
| Theme misses the target after 60 days | Retire or pause | Budget freed |
Each split adds work. The new ad group needs its own ads, its own negative keywords, and its own bid target. It also needs enough conversions to be judged, which small groups often lack.
Merging ad groups without losing conversion history
Merge when two ad groups search for the same thing. Keep the ad group with the stronger conversion history, move the other group's keywords, ads, and negatives into it, then pause the empty group.
Merge without losing history
- Keep the ad group with stronger conversion history
- Move other group's keywords into it
- Move ads and negatives into it
- Pause the empty group
Combining near-identical keywords concentrates relevance. Quality Score reflects expected click-through rate, ad relevance, and landing page experience, and higher scores can lower what you pay per click.
Merging also feeds automated bidding. Strategies such as Target CPA and Maximize Conversions, described in the Google Ads overview, need enough conversion volume in one place to set a workable target. Two thin ad groups may each hold too little.
Retiring an ad group that cannot meet its target
Retire means pause or delete, and it should follow a fair test. Give the ad group its own ads, negatives, and time. If it still misses the target cost per acquisition, the theme is the problem, not the settings.
Retiring is not failure. The budget moves to ad groups that convert, and the account gets one less place for overlap to hide.
Health advertisers in the United States face extra constraints. Marketing messages about treatment can require patient authorization under the HIPAA marketing guidance, so a thin ad group is hard to defend.
Example: consolidating twelve ad groups into seven
A home services advertiser ran twelve ad groups across two campaigns. Four pairs targeted the same service with the same landing page. Two ad groups held one keyword each and never cleared the target cost per acquisition.
The rebuild merged the four pairs into four ad groups, split one mixed-intent group in two, and paused the two thin ones. That left seven ad groups, fewer self-competing auctions, and a search terms report that was easier to read.
Ad group review checklist
Work through these steps each month:
Monthly ad group review
- Search terms exported and tagged by intent
- Overlap pairs listed with merge or negative decision
- Split candidates confirmed to need different ads
- Thin ad groups judged against target CPA
- Paused ad groups archived with their negatives
- Export search terms for every ad group and tag each term by intent.
- List ad group pairs whose top converting terms overlap.
- Check each split candidate for ad copy and landing page differences.
- Judge thin ad groups against the target cost per acquisition.
- Search terms exported and tagged by intent
- Overlap pairs listed with a merge or a negative keyword decision
- Split candidates confirmed to need different ads
- Thin ad groups judged against target cost per acquisition
- Paused ad groups archived with their negatives
Ad group work settles overlap inside a single theme. The level above it decides offers, query controls, and accountable automation, and what to keep and what to drop covers those campaign choices.
