Google has launched Search Themes, a new feature for Performance Max campaigns that give performance marketers a new way to provide additional signals in PMax and expand your ad reach.

Performance Max uses information from your assets, feeds, and landing pages to inform its ad placement decisions. That means it has the lion’s share of control over your ad targeting. But with Search Themes, you can input your own keywords to fill the gaps in your campaign reach.

So how do Performance Max Search Themes work, and when can you use them? In this marketer’s guide to Search Themes, you’ll learn everything you need to know about setting up and monitoring Search Themes in your PMax campaigns.

What are PMax Search Themes and how do they work?

Google’s release notes explain what Search Themes are and how they’re intended to help marketers:

“A new beta called “search themes” in Performance Max provides you with an easy way to guide Performance Max to serve on placements that you may not be reaching yet.

"Performance Max currently looks at your assets, feeds, and landing pages to predict which placements, including search queries, will perform well for your campaign. Now with the search themes beta, you can fill in gaps by adding information about your business that you expect to perform well. By combining your expertise with Google AI you’ll be able to expand your reach on all channels, including Search.”

Search Themes allow marketers to provide more signals to Google about which search queries are likely to be relevant to your product, service, or business. This adds more depth to PMax’s knowledge of your brand, so it can put your ads in front of more relevant audiences.

However, marketers must remember that Search Themes don’t work like the traditional keyword targeting in standard Search campaigns. They’re simply signals the PMax algorithm can learn from (or disregard) as it sees fit.

When to use Search Themes

Google offers some useful examples of when Search Themes can be used effectively:

• Your landing page doesn’t have complete details or the latest updates about the products and services you offer.
• You’ve just expanded into a new market or launched a new product or service where your campaigns don’t have extensive performance history.
• You are launching a new promotion or sale for the holiday season where you don’t have extensive performance history.
• You want to expand your reach within Performance Max—including on Search inventory in Performance Max—and ensure you have comprehensive coverage on important business themes.
• You want to provide important information to help your campaign ramp up and optimise performance faster.

Ultimately, these break down into two main reasons to use Search Themes:

1. There isn’t enough content on your website or landing page to give Google all the information it needs about the search queries you want to be found for.
2. You want to optimise PMax campaign performance more quickly.

Michelle Morgan at Paid Media Pros explains why your landing page(s) might not have enough information for Google to effectively reach new audiences:
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I’ve seen many times where companies will run lots of conversion rate optimisation tests on their landing pages, and a shorter, less informed page will actually perform better. So you might not have every single detail available on your landing page for Google to discern and find all the relevant search queries.

Michelle Morgan
Co-Founder, Paid Media Pros

What marketers are saying about Search Themes

Like with many aspects of Performance Max, Search Themes are proving controversial among marketers.

In a recent edition of his LinkedIn PPC News newsletter, PPC consultant Yoann Ferrand provided a round-up of Search Themes analysis from Thomas Eccel, Navah Hopkins, and Alex van de Pol. Here, we take a look at the reaction from other marketers on both sides of the fence.

Some are excited about Search Themes and other PMax developments, suggesting Google is restoring some control to advertisers, following claims that Google has reduced advertiser control over ad spend:

Others have even discussed how this signalling solution could replace traditional keyword targeting in future, as it gives more people scope to succeed with PPC (which is PMax’s purported goal in the first place):

Other marketers, however, are less convinced. Some suggest that, rather than giving inexperienced advertisers another string to their bow, Search Themes could actually be dangerous if used incorrectly:

Others have experienced an increase in PMax cannibalisation since the launch of Search Themes (we’ll talk more about why this happens shortly):

The increasing dependence on AI in PPC automation has also divided marketers. Some suggest Google is cynically using it as a sales tool that actually increases the workload for PPC specialists, while others believe Google’s AI is often capable of filling in campaign gaps by itself:

As with many new features, there are pros and cons to Performance Max Search Themes. That’s why it’s best to test Search Themes on your own campaigns and see the impact for yourself. Let’s find out how you can add Search Themes to your Performance Max campaigns.

How to add Search Themes to PMax campaigns 

Here’s a step-by-step guide to adding Search Themes to your PMax campaign:

1. Sign in to your Performance Max account. Navigate to the campaign and asset group you want to add Search Themes for.

2. Click Search Themes in the panel on the left to bring up the Signals page.

3. Enter a Search Theme that’s relevant to your campaign and press enter to add this to your asset group.

4. Add up to 25 Search Themes per asset group.

Search Themes and cannibalisation 

It’s really important to be aware of the risk of campaign cannibalisation when using Search Themes. This is due to the level of prioritisation Google has assigned Search Themes versus standard Search campaigns:

“On Search inventory specifically, Search Themes in Performance Max campaigns will have the same prioritisation as your phrase match and broad match keywords in Search campaigns. Exact match keywords that are identical to the search queries will continue to be prioritised over search themes and other keywords.”

This means exact match keywords in your Search campaigns take precedence over all other targeting types. But PMax Search Themes have been given the same priority level as close variant phrase and broad match keyword targeting in Search.

Phrase and broad match keywords that exactly match the search term will be prioritised over Search Themes. But PMax Search Themes can still show for very close variants such as changes to word order or misspellings - meaning cannabalisation is still at play. Ultimately, Ad Rank is the tie breaker between Search Themes and close variant phrase and broad match keywords, so it's important to stay mindful of it's impact in this regard.

If all your Search campaign keywords are phrase or broad match, there’s a high risk of PMax cannabalising some of them. The only way to prioritise traffic to Search rather than PMax is to use exact match keywords in your Search campaigns.

If you want to see performance for specific keywords through your existing Search campaigns rather than PMax, make sure they’re added as exact match keywords in your existing campaigns.

Tracking Search Themes performance 

Unfortunately Google hasn’t (yet) provided much functionality for tracking the performance of your Search Themes. As with PMax audience signals, once Search Themes are set up, you won’t get any insights into how each theme is performing. You can’t even see how Search Themes compare with audience signal performance. 

Currently, the only way to track Search Theme performance is to see how well your campaigns perform with and without Search Themes added. Michelle explains how to do this:
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"I would suggest doing some sort of line of demarcation on the calendar, run your Search Themes for [a week to] a month, then compare the performance for the month where the Search Themes were active to the month prior, when they weren’t active."
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Michelle Morgan
Co-Founder, Paid Media Pros

This isn’t a perfect system for analysing results, as it’s not an entirely fair test. But it will give you an idea of how your chosen Search Themes might affect the overall performance of your PMax campaigns.

To find out more about optimising advertising efficiency in PMax, download our Performance Max Playbook.

Brand exclusions and account-level negative keywords 

If you’ve already set brand exclusions and account-level negative keywords in your Google Ads account, Google has confirmed that Search Themes will respect these. So you don’t need to worry about your ads appearing for unwanted search terms if these have already been excluded from your campaigns. 

Search Themes reporting 

Search Themes have limited reporting functionality, at least for now. Google states:

“You’ll be able to see the search categories that your ads matched to in your search terms insights at both the campaign and account levels, and associated conversion performance. You can now view search term insights for custom date ranges, download your data, and access it via the API.”

So you won’t be able to see performance of each Search Theme within your campaign. But you can use search terms insights to view the search categories Google has used based on your applied Search Themes.

Google has noted that improved search terms insights will be available from early 2024, so hopefully we’ll see more useful reporting features for Search Themes in future.

Search Themes and PMax custom segments 

Search Themes are set to replace custom segments based on search activity from 2024. Google will automatically update your PMax account to reflect this, meaning you’ll no longer be able to add or edit custom audience segments based on past search activity. If you currently rely on these, it’s a good idea to get used to Search Themes now.

Custom segments based on interests, affinities, apps, and competitor URLs will still be available to add and edit after this update.

Best practices for setting up Search Themes 

Bob Meijer and Miles McNair at PPC Mastery have compiled a list of 11 best practices you should use when setting up Search Themes in your PMax account. Here’s their list in full:

• Use broad Search Themes
• Don’t use duplicates or close variants
• Don’t expect massive changes in the beginning
• Align Search Themes with assets and messaging
• Use Search Themes to ramp up (new) pMax campaigns
• Analyse by checking the search term insights of your pMax campaigns
• Monitor your pMax spend allocation script: review impact on Search campaigns
• Search Themes will respect Brand Exclusions and account-level negatives
• You can add up to 25 Search Themes per asset group, but it’s ok to use fewer
• Understand that traffic from Search Themes go to landing pages from Final URL Expansion, Page Feeds, and “URL Contains” settings.
• Understand that Search themes will have the same prioritisation as your phrase match and broad match keywords in your Search campaigns. AdRank plays a huge role here.

Watch our profitable Performance Max strategies webinar with Miles for more tips, then check out our best practices for Performance Max to improve your campaign results.

Protect Your PMax campaigns with Lunio

Search Themes may give advertisers a little more control over their PMax campaigns. But these automated campaigns are still vulnerable to invalid traffic that skews ad performance and drains ad spend, ultimately eating into your profit margin. 

Lunio protects your PMax campaigns by stopping invalid traffic from clicking your ads, so more of your budget can be spent driving genuine users to your site. One of our enterprise retail clients reduced their costs by 25% and drove a 48% increase in direct sale conversions after just one month.