We Tested Display Expansion for Search & Here’s What We Found

Over the last several months, Google has recommended enabling the Google Display Network for Search campaigns that are not meeting their daily budget goals. Essentially, no new assets are required, as Google will re-purpose the text ads the campaigns are currently running, though you have the option to add Responsive Display Ads to help optimize performance.

Google hypothesizes that by expanding campaigns to serve cross-channel, marketers will be able to capture incremental conversions at similar CPLs to search campaigns.

We tested this recommendation on campaigns targeting both the US and UK here at Seer and wanted to share the results!

---

Recommendations

 TL;DR: Enabling the display network for search campaigns contributed to an overall increase in cost and CPL, with minimal incremental conversions

We recommend only testing Display Expansion for Search campaigns that meet the following criteria:

• The campaign is not meeting daily budget goals
• The campaign generally sees low volume
• The campaign optimizes towards a variety of conversion actions (clicks and conversions, for example)

Methodology

We enabled the Google Display Network and compared performance period-over-period after implementation.

Test A: US Targeted Campaigns

• Goal: Increase conversion volume at a similar CPL for campaigns that were not meeting their budget goals and are using a tCPA bidding strategy.
• Hypothesis: The Google Display Network will utilize available budget from search campaigns to capture additional conversions at similar CPLs.
• Results: After the initial performance check-in (two weeks after launch), overall campaigns saw a +100% increase in cost, +32% increase in conversions and a +51% increase in CPL.
  • Most of the conversions were driven by campaigns that either historically struggled with driving traffic or were optimizing towards a variety of conversion actions (both top-of-funnel and bottom-of-funnel).

If you have campaigns that aren’t seeing an increase in traffic after adjusting their bidding strategies, cutting out wasted spend, adjusting their targeting, etc – these are great candidates for a Display Expansion test!

For other lead-gen focused campaigns that usually spend their budgets in full, CPL increased by as much as +170% after implementation while driving no incremental conversions. 

These results were statistically significant, so we disabled the GDN for any campaigns that had not driven a conversion since launch, and kept the GDN enabled for remaining campaigns. As a next step, we will also test the impact the addition of Responsive Display Ads has on performance.

Test B: UK Targeted Campaigns

• Goal: Similar to our US campaigns, increase conversion volume at a similar CPL for campaigns that were not meeting their budget goals and are using a tCPA bidding strategy.
• Hypothesis: The Google Display Network will utilize available budget from search campaigns to capture additional conversions at similar CPLs.
• Results: After the initial performance check-in (two weeks after launch), overall campaigns saw an +89% increase in cost, -33% decrease in conversions and a +184% increase in CPL.
  • Similar to the US test, most display conversions were driven by campaigns that either 1) historically struggled with driving traffic or 2) were optimizing towards a variety of conversion actions (both top-of-funnel and bottom-of-funnel). The biggest difference between UK and US is that these UK campaigns actually saw a significant decrease in conversions and a much higher increase in CPLs than the US campaigns.

These results were statistically significant, and we ultimately ended the test for campaigns that had not driven a conversion on the display network since launch in order to help improve efficiencies. As a next step, we will be testing the addition of Responsive Display Ads to those with the Display Network enabled.

In Conclusion

Overall, we don’t recommend using display expansion unless your campaign meets the criteria we mentioned:

• The campaign is not meeting daily budget goals
• The campaign generally sees low volume
• The campaign optimizes towards a variety of conversion actions (clicks and leads, for example)
  • As Display tends to be an awareness initiative, it is more effective at driving those upper-funnel conversions than a typical search campaign.

However, Google is always optimizing their networks and there are additional iterations to test in terms of bidding strategies and ad assets. Have you tried this for any of your campaigns? Let us know in the comments!

---

Sign up for our newsletter for more posts like this delivered straight to your inbox: