Search themes in Performance Max: how to give Google AI direction

What are search themes in Performance Max?

Search themes are signals you add per asset group to a Performance Max campaign. They tell Google AI which searches and topics your customers use. Google treats that information as a complement to what it already infers from your landing pages, your ad assets and your product feed if you have one.

The difference with classic keywords is fundamental. A keyword in a Search campaign is targeting: you decide what you bid on. A search theme is a hint: you give direction, but Google AI ultimately decides which searches trigger your ads. Think of it as steering rather than driving.

Google Ads Help explicitly positions search themes as a complement, not a replacement for what the AI learns on its own. They are most valuable when your website or assets do not yet contain all the information the system needs. Think of a new product, a new service or an audience that uses very different words than your web copy does.

Why are search themes especially interesting for SMEs?

For SMEs, search themes solve a familiar problem: Performance Max often feels like a black box. You put budget and assets in, but you have little grip on the searches you show up for. Search themes hand part of that steering wheel back to you, without throwing the automation overboard.

That is extra valuable when your offering is specialised or local. An installer, accountant or manufacturing business often serves a niche where customers use very specific terms. If that language is not yet literally on your website, Google AI lacks context. Search themes let you fill that gap deliberately, in your customer's own words.

On top of that, an SME account usually has less conversion data than a large account. The less data, the longer it takes for the AI to recognise your ideal customer. Clear signals, including well-chosen search themes, help the system look in the right corner sooner. It is not a guarantee of results, but it is a way to feed the learning phase with focused input.

How do search themes work under the hood?

Search themes act as input for the prediction model of Performance Max, not as a hard filter. Google combines your themes with everything it already knows from your assets, landing pages and feed. Based on that, the system decides which searches and auctions give your ads a realistic chance.

It is important to understand the pecking order relative to your Search campaigns. According to Google Ads Help, an exact match keyword that is identical to the search query always takes priority over a search theme. In other situations, search themes carry a weight comparable to phrase match and broad match keywords. Your brand Search campaign stays in the lead, provided it is set up tightly.

You also keep control through exclusions. According to Google Ads Help, search themes honour your account-level negative keywords and your brand exclusions. And the traffic that comes in through search themes shows up in your campaign's search terms insights. That is how you verify whether your signals do what you expect.

Search themes vs. keywords vs. DSA: the differences at a glance

The three instruments look similar, but each plays its own role. Keywords give you maximum control within Search campaigns. Dynamic Search Ads (DSA) let Google build ads based on your website content. Search themes steer the AI of Performance Max. The table below puts the key differences side by side.

The practical conclusion for SMEs: this is not an either-or choice. A Search campaign with solid keywords often remains the backbone of your account. Performance Max with well-chosen search themes adds coverage where keywords stop, and captures search behaviour you could never have predicted upfront.

How do you set up search themes? The step-by-step plan

You set up search themes per asset group, not at campaign level. That is the most important mental step right away: each asset group should ideally represent one product, service or audience, with its own themes that fit seamlessly. The steps below follow the approach as described in Google Ads Help.

When entering themes, mind your customer's language. Write themes the way someone would search, not the way your internal product names read. 'Emergency boiler repair' tells Google AI far more than a model number nobody outside your industry recognises.

1. Sign in to Google Ads and open your Performance Max campaign from the campaign overview.
2. Click Asset groups and select the asset group you want to add search themes to.
3. Within the asset group, open the signals section and choose search themes.
4. Add themes that describe what your customers search for, in their own words.
5. Save the asset group and repeat this per asset group, each time with its own fitting themes.
6. After a few weeks, review the search terms insights and sharpen your themes where needed.

How do you choose strong search themes?

Strong search themes describe search intent your website does not yet radiate on its own. So do not start with a brainstorm, but with an inventory: which searches, questions and problem descriptions do customers use that appear nowhere on your site verbatim? That is exactly where a theme adds the most.

Good sources are the search terms reports from your existing Search campaigns, the questions customers ask on the phone and the wording they use in quote requests. Translate those into short, concrete themes per asset group. Keep each asset group thematically clean: themes about service A do not belong in the asset group for service B.

Avoid two pitfalls. The first is stuffing everything with variations of the same concept; the AI generally understands synonyms just fine, so choose different angles instead. The second is adding themes that merely look similar but actually serve a different audience. Every theme is an invitation to the AI. So only invite the right visitors.

How much control do you keep over where you appear?

More than many advertisers think, but less than with a classic Search campaign. Search themes themselves are not hard targeting. Your control comes from combining them with exclusions: brand exclusions prevent Performance Max from riding along on brand names you do not want to appear for, and negative keywords filter out unwanted traffic.

According to Google Ads Help, search themes respect exactly those two mechanisms: your brand exclusions and your account-level negative keywords. So set those up properly before you add themes. Otherwise you are giving the AI an accelerator without a brake, and with paid traffic that is the last thing you want.

Also make it a habit to review the search terms insights regularly. Do you see searches that deliver nothing or do not match your offering? Then add exclusions or rephrase your themes. Steering with signals is not a one-off setting, but an ongoing rhythm of reviewing and adjusting.

From DSA to AI Max: what does the shift mean?

Google is visibly moving from standalone automations to broader AI solutions. Dynamic Search Ads, the campaign type that generates ads from your website content, is shifting towards AI Max and Performance Max as part of that movement. For the current planning, conditions and limits we deliberately refer you to the official Google Ads channels, because those details change regularly.

What does this mean in practice if you run DSA today? Map out which searches and landing pages your DSA campaigns currently cover. That knowledge is worth gold in a transition: your best performing search terms and pages translate almost directly into search themes and into asset groups with the right focus.

The underlying lesson matters more than any precise migration date. Google asks advertisers less and less for individual settings and more and more for good input: clear signals, strong assets and reliable conversion data. If you master search themes now, you are prepared for the direction the entire platform is moving in.

How do you judge whether your search themes are working?

The honest answer: not on day one. Performance Max needs time to learn to work with new signals. So judge search themes on the trend over several weeks, through the search terms insights and the results per asset group, and not on a single day or an isolated week.

Look at three things in the search terms insights. Do you appear for searches that match your themes? Do those searches produce serious enquiries or sales? And do you see categories emerging that you would rather exclude? That way you tie each theme to concrete search behaviour instead of a gut feeling.

If a theme does not work, do not delete it straight away. First ask whether the problem really sits with the theme: maybe the landing page does not match, your assets do not live up to the promise or your conversion tracking is faltering. Search themes are a steering wheel. The rest of the car has to run too.

Not sure whether your Performance Max campaign is getting the right direction? We will take a look with you, no strings attached.