Google Ads Negative Keyword Strategy: Three Layers

Money leaks out of a Google Ads account in two places: bidding on the wrong keyword, and the right keyword catching the wrong search. The keyword list solves the first; negative keywords solve the second. In most accounts the keyword list gets weeks of attention and the negative list is never built.

This guide describes the three layer negative structure we use in the accounts we run, and the weekly routine that feeds it.

What a negative keyword does

A negative keyword stops your ad from showing for a particular search. If you bid on "web design" and also appear for "free web design", adding "free" as a negative removes that search. No impression, no click, no spend.

There is a second effect. Clicks from irrelevant searches do not convert, so they lower your click-through rate and therefore your quality score, and a lower quality score raises your cost per click. The negative list manages unit cost, not just waste.

Layer 1: the account-wide shared list

The first layer holds searches that will never fit your business model. They do not change between campaigns, so they are written once and attached to every campaign as a shared list.

Typical patterns: free, torrent, crack, download, how to, DIY, job, internship, salary, course, training, complaint, scam. If you sell a service, someone searching "how to" is not your customer; if you do not sell training, neither is someone searching "course".

Building it as a shared list is about maintenance. A new campaign is attached with one click, and a newly learned pattern is written once and applied everywhere.

Layer 2: campaign level

The second layer is specific to the campaign. "Logo" may be a negative in your web design campaign because logo work is a different service. The same word is not a negative in your branding campaign, where it belongs.

This layer also draws the boundary between services. If every service has its own campaign, campaign negatives stop those campaigns catching each other's searches. Otherwise two of your own campaigns bid against each other on the same search and you raise your own cost.

Layer 3: ad group and cross negatives

The third layer is the finest and the most often skipped. If a campaign has several ad groups, they can eat each other's traffic. A "corporate web design" group and an "e-commerce web design" group can both enter a search containing "web design".

The fix is the cross negative: each group's distinguishing word is added as a negative to the other groups. Which search lands in which group becomes predictable, and your reporting becomes readable.

This layer is the natural complement of tight thematic grouping. When groups are kept narrow it is clear which keyword belongs where, and cross negatives are easy to write.

Match types for negatives

Negative keywords have match types too, and they behave differently from positive ones. Close variants are not included on the negative side: adding "free" does not automatically block plurals or misspellings. Common variants have to be written out.

In practice broad negatives work well for single generic words, phrase negatives for two or three word expressions. An exact negative is for blocking that one search only; used too widely it can cut real traffic.match type

The weekly routine: the search terms report

All three layers are fed from one source: the search terms report. It shows which searches your keywords actually caught. Your setup is an assumption; this report is the only document that tells you whether the assumption held.

The routine is simple. Once a week open the report for the last seven days, scan searches that took clicks but did not convert, and add the irrelevant ones to the right layer. General pattern goes to the account layer, service specific to the campaign, group overlap to the ad group.

New accounts need a closer look in the first three or four weeks. As the account matures a weekly rhythm is enough, but in a neglected account the negative list ages too.

Three common mistakes

First, writing the negative list once at setup and never opening it again. A negative list is a living document that takes a few lines from the search terms report every week.

Second, negating too aggressively. Adding "price" looks sensible at first, but someone searching for a price is often the closest to buying. Check whether a search actually brings customers before excluding it.

Third, writing negatives at the wrong layer. A pattern that belongs account-wide but is written into one campaign leaves the same waste in the others; a campaign specific word written account-wide cuts real traffic for another service.

Conclusion

Negative keywords are the cheapest optimisation in Google Ads: they require no bid increase and cut waste directly. Build the three layers, feed them weekly from the search terms report, and avoid being aggressive. In most accounts these three steps produce the most visible gain of the first month.

If you would like us to review the negative structure in your account, you can reach us from our Google Ads management page. The full picture is in our Google Ads guide.