Glossary

Search Term Isolation (STI)

Last updated: April 8, 2026

Definition: What is search term isolation?

Search term isolation (STI) is the practice of deliberately pulling individual Amazon PPC search terms out of broad campaigns and moving them into their own, tightly targeted ad groups or single keyword campaigns. The goal is to give every profitable search term its own control layer with an individual bid, its own budget, and its own performance reporting.

The method is used above all as part of a clean campaign structure, often in combination with the Match Type Funnel. There, search terms gradually move from auto, broad, and phrase campaigns into exact match structures, where each exact match keyword is steered in isolation.

Why search term isolation makes sense

In broad campaigns, many different search terms blend into a single performance figure. That makes it hard to spot the genuinely profitable terms and scale them deliberately. Search term isolation solves exactly this problem: every relevant search term becomes visible, measurable, and individually controllable.

STI also helps distribute budget efficiently. Instead of a single top term swallowing the entire campaign budget and blocking other terms, each isolated search term gets its own spending limit – complete with a clear bidding strategy.

How search term isolation works in 4 steps

1. Identify search terms

The Search Term Report shows you every search term your ads were served on. Filter for terms with enough conversions or high spend.

2. Move into an exact match campaign

For each selected search term (or a group of related terms), create its own ad group or campaign using exact match. This ensures your ads are only served on exactly that search term.

3. Exclude it in the source campaign

Add the isolated search term to the original broad/phrase campaign as a negative exact. This prevents duplicate impressions and self-competition.

4. Individualize bid and budget

Assign the isolated campaign its own performance-oriented bid and an individual budget. Based on the performance, you can now fine-tune with precision.

A practical example

A seller of outdoor equipment runs a broad match campaign with the keyword “hiking backpack”. In the Search Term Report, they notice that the search term “hiking backpack 30l mens” is especially profitable:

• 42 clicks, 9 conversions, ACoS 12%
• Comparison term “hiking backpack” (general): ACoS 38%

Instead of letting this profitable search term keep running in the broad bucket, the seller isolates it into its own exact match campaign with a higher bid in order to win the auctions reliably. At the same time, they add “hiking backpack 30l mens” as a negative exact to the broad campaign so there is no self-competition. The result: greater visibility for the top term, clear performance reporting, and a cleaner overall structure.

Common pitfalls

Forgetting negative keywords: If you isolate a search term but don't exclude it in the source campaign, you pay for the same term twice.
Isolating too early: Search terms with too little data (e.g. only 1–2 clicks) can't be evaluated reliably. Wait for statistically meaningful figures.
Overly granular structures: Building hundreds of individual campaigns for every single term drowns you in admin overhead. It's smarter to bundle related terms into a shared ad group.
No regular review: The Search Term Report should be checked at least weekly to spot new candidates for isolation.

Frequently asked questions (FAQ)

When should I isolate a search term?

A common rule of thumb: once a search term shows at least 2–3 conversions or a clear share of spend in the Search Term Report. The key is that the data set is large enough to make a well-founded decision about bid and budget.

What is the difference between STI and a Match Type Funnel?

The Match Type Funnel is the overarching methodology that defines how search terms move from auto through broad and phrase to exact campaigns. Search term isolation is the concrete step within that funnel in which a search term is pulled out of a catch-all campaign and moved into its own structure.

Does STI make sense for small accounts too?

Yes, but in a slimmed-down form. Even small sellers benefit from isolating their 5–10 most important search terms. Isolating hundreds of terms without enough data only creates unnecessary complexity.

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