Search partner targeting is an on-by-default setting in Google Ads that can lead to budget being wasted on low quality traffic. We might reasonably expect to see similar performance between search partner sites and the Google search network, but a recent analysis by our data science team tells a different story.

Before we jump into the research (and share some nuances to consider when optimising search partners), we should quickly recap the basics of search partner targeting.

What are search partners?

All searches that happen on sites other than Google itself fall into the search partner category. This means there are more than we might first imagine.

Sites like YouTube and Amazon embed ads from Google after a visitor searches for a video or product. Other large websites like The Guardian or W3Schools use Google Custom Search Engine (CSE) to power their site searches.

As of writing, there are 250,791 live websites using Google Custom Search. That’s a lot of potential search partners! Given the scale of search partners, we wanted to find out to what extent they are a worthwhile investment.

Search partner data analysis

We looked at a large dataset of accounts that have not used Opteo before (to make sure that the data is a true representation of real-world Google ads accounts). We then filtered the dataset so that we were left with around 10,000 Google Ads accounts with at least 10 conversions via the Google Search network and search partner sites.

Looking at the difference in CPA between the Google Search network and search partner sites, the median difference puts search partner conversions at around 7% more expensive than the equivalent search conversion via the Google Search network.

We plotted the differences in CPA on the histogram above. The distribution has a slight positive skew and a central tendency but also some surprisingly long tails. In other words, search partner performance can vary wildly, as such, we should keep an eye on it. Let’s look at how to evaluate and optimise search partners for your accounts.

How to manually analyse and exclude search partners

The basic workflow of optimising Google search partner performance involves selecting the relevant campaigns, breaking performance out by network, and comparing results. For campaigns where search partner performance is unacceptable, you'll find the option to opt out of search partners in campaign settings.

Here's a step by step guide for reference:

• First, filter your account for Search and standard Shopping campaigns (only select enabled campaigns).
• Second, pick a date range where both Search and Search Partners were running alongside each other to ensure a fair, apples-to-apples comparison.
• Third, isolate Search Partner performance by selecting Network (with search partners) as a segment.

• Next, compare the CPA of Search partners and Google Search. You can do this for each campaign, or as a total towards the bottom of the campaign view.

• Fifth, if search partner performance is unacceptable, you can disable search partners under the Networks heading in an individual campaign's settings.

• Finally, watch out for auto-applied recommendations! Many advertisers don’t realise Google may be making changes to their accounts behind the scenes. There's no use in switching off search partners if Google is going to switch them back on automatically!

Optimising search partner performance in Opteo

When ads perform poorly on search partner sites, Opteo will recommend disabling search partners for the relevant campaigns. Our algorithms do the analysis on your behalf, while also taking into account some additional nuances like comparing performance with existing targets and ensuring there's enough data to make reliable decisions.

Using campaign groups to aggregate performance data

One of the most common roadblocks to making decisions about optimisations — like leaving search partners on, or turning them off — is having enough data to be statistically confident. If we compare search partner performance to Google Search performance campaign by campaign, the likelihood is, most campaigns wouldn't have enough data to make a reliable, statistically sound decision.

To solve this, we can group campaigns together and look at their aggregate performance. But in order to do that, we need to understand which campaigns should and shouldn't be grouped together. For example, you probably wouldn't want to mix data from your brand campaigns and generic performance campaigns together, because the acceptable level of performance is so vastly different for each type of campaign. They may even use different conversion types.

In Opteo, setting up campaign groups allows our algorithm to understand which campaigns should be compared with each other, which conversion types are relevant, and what your desired targets are. Once campaign groups are set up, Opteo can aggregate campaign performance data and understand a particular campaign's performance relative to the other campaigns in its group (useful in instances when there is no defined target).

Campaign groups and performance targets set the basis for our decision making. If search partners are performing worse than their target? Turn them off. Performing better? Leave them on. Seems simple enough, but there are some other factors to consider, let’s layer in some refinements.

Imagine a scenario where, within a given campaign group, search partners are performing worse than their target, but better than Google Search:

In this case, it would be a mistake to cut search partners, so we can refine our decision making process to exclude search partners only when search partner CPA is worse than both Google Search CPA and the target CPA.

High volume campaigns

It’s reasonable to assume that even in campaign groups where search partners are performing poorly, there could be individual campaigns where they contribute positively. Instead of switching off search partners for all campaigns inside a given campaign group, Opteo picks out campaigns that have enough volume to be evaluated by themselves.

To work out which campaigns have enough volume to warrant a campaign-level search partner performance evaluation, Opteo compares clicks to the minimum click threshold of the parent campaign group, as below:

minClicks = (1/AvgConvRate)*X

In a given campaign, if search partner clicks are above the minimum threshold (i.e. the campaign has accumulated enough search partner clicks to, on average, produce X conversions) then we can evaluate that campaign by itself.

This way, important high volume campaigns can be treated individually, and lower volume campaigns (which do not have enough data to make a per campaign decision) can be grouped together and treated as a collective.

In the example below, Campaign One, Campaign Two, and Campaign Three each have more clicks than the minimum threshold and so are treated individually. Campaign One and Campaign Three have search partner CPAs above the campaign group target, so search partners are turned off. Campaigns Four, Five and Six don't have enough clicks to reach the minimum threshold, so their performance data is aggregated. The aggregate search partner CPA is above the campaign group target, so search partners are switched off for these campaigns as well.

Wrap up and takeaways

I hope you picked up something useful from this post. Here’s a quick recap of the key points:

• Search partner performance varies from campaign to campaign, and account to account, so it's certainly worth monitoring regularly.
• Evaluate search partner performance by comparing the CPA (or ROAS) of search partners to both Google Search and your desired target for that campaign.
• Use the “minimum clicks” method to identify campaigns that have a high volume of search partner clicks. Make a decision about search partners campaign by campaign for high volume campaigns.
• For campaigns that don’t pass the minimum clicks test, consider grouping their performance data together (only if they belong to the same campaign group) so that you have enough data to make a decision.
• Look out for auto-applied recommendations — amongst other potentially undesirable changes, auto-apply might switch search partners back on automatically.
• Given the large variance in search partner performance, regular testing can be worthwhile. If you're looking to increase volume, search partners can be a sensible approach to expanding your audience.