A Beginner’s Guide to Creative Testing for Google App campaigns

7 Min Read

Google App campaigns (previously Universal App Campaigns or UACs) were first introduced in 2015 and have since become the go-to for app marketers to access all of Google’s advertising inventory – search, display, Gmail, YouTube, Play Store and AdMob – in one place.

With bidding, placement and targeting being optimized by machine learning in Google App campaigns, ad creative is now critical for app marketers looking to gain an edge over their competitors.

But how can one actually optimize creative for performance in App campaigns?

From our own experience in running ads, only one in every ten ads turn out to be what we call a “unicorn ad” and vastly outperforms the rest. A clear creative testing strategy is hence necessary to identify the ads which work best for your app and audience.

How ads are created in Google App campaigns

Unlike previous campaign types where finished creatives are used to run ads, Google App campaigns operate on an asset-based model. Advertisers have to provide individual creative assets in each of the following categories:

  • Text
  • Image
  • Video
  • HTML5

These assets are then mixed and matched to create multiple ad permutations, which are served across different placements at various times to individual users.

Given how Google’s machine learning algorithm analyzes audience signals to determine which user would respond best to a particular permutation and hence be served that ad, providing Google App campaigns with as many assets as possible allows you to reach a broader target audience more effectively.

Getting started with creative testing for App campaigns

Without a clear plan in place for creative testing, it is near impossible to identify the types of ads which drive the best results for your Google App campaigns. Yet, the sheer number of asset types, sizes and potential variables for testing can be a source of confusion for many advertisers.

From our experience at Creadits building creative testing strategies for top mobile game publishers and Fortune 500 businesses alike, here’s a step-by-step approach if you have no idea where to start.

Step 1: Decide on a concept to test

Rather than dive straight into producing your ad assets, take a step back to think about the concept you want to be testing.

The concept is the big idea which ties all of your ads together and guides the production of individual assets. You should also have a hypothesis for each concept you are testing, which is based on what you expect the results to be like and why so.

For example, you can hypothesize that a concept based on real life players competing with each other would resonate with your target audience of casual gamers because they tend to play most with close friends and family.

Try looking at your competitors in the same app or game category for some inspiration with regard to concepts. Whether it may be on Facebook, Twitter or Google, they would have probably nailed down a successful formula by now.

Step 2: Build and upload your assets

Once you have decided on concepts to test, it’s time to get down to producing each of the individual building blocks of your ads.

Text Assets

Optimal number of assets: 4 lines of text, up to 25 characters each

What you should be testing minimally: 4 lines of text, up to 25 characters each


Text is the only asset group you definitely have to create yourself, rather than rely on Google to automatically generate for you. Fortunately, it also requires the least amount of resources to produce so there really isn’t any excuse to not upload the maximum number of four text assets.

Bear in mind that these text assets may be used individually, together, or with other types of assets across all types of inventory on the Search Network, Display Network and AdMob. Each line should make sense both on its own and when placed next to another asset, in any given order.

For starters, try 1-2 text ideas with less than 20 characters to prevent your copy from being cut off abruptly on certain placements (e.g. Gmail). Test varying lengths with your text ideas to see what works better for your Google App campaign, and take the opportunity to refresh once you can draw conclusive results.

Image Assets

Optimal number of assets: 20 images, across 20 different sizes for the Display Network

What you should be testing minimally: 20 images, 2 in each of the top 10 high-reach dimensions

The entire list of sizes for image assets may appear overwhelming at first glance, but these different dimensions are not made equally. If you’re short on time and resources, here are the top 10 most frequently served ad sizes to prioritize, from most to least important:

  • 320 × 480 (Portrait Interstitial)
  • 480 × 320 (Landscape Interstitial)
  • 300 × 250 (Square)
  • 1024 × 768 (Tablet)
  • 768 × 1024 (Tablet)
  • 320 × 50 (Banner)
  • 1200 × 628 (Landscape Image)
  • 728 × 90 (Leaderboard)
  • 300 × 50 (Banner)
  • 320 × 100 (Banner)

We would recommend testing 2 variations in each of the above 10 sizes to begin with. That would give your campaigns access to around 95% of all available inventory on AdMob.

Every App campaign is unique though. It is still advisable to upload and test all 20 different sizes to find the right balance for your business and target audience eventually. Reach out if you need help with this!


Providing your own assets in every size also prevents Google from taking what’s available on the iOS App Store or Google Play Store to automatically generate assets. You will not have any control over the messaging or quality of these automatically generated assets, and this may not deliver the best results for your app campaign.

Video Assets

Optimal number of assets: 20 videos, across landscape (16:9), square (1:1) and portrait (2:3) ratios

What you should be testing minimally: 9 video variations, adapted from one original video to fit different aspect ratios and lengths

Videos tend to bring the most valuable users for your app, but they also require more effort to produce.

The good news is one original video can go a long way, when you create variations based on aspect ratio and length. With 6s, 15s, 30s videos in each of the three available ratios of 16:9, 1:1 and 2:3, you would already have a minimum of 9 videos to use for testing.

While around 70% of impressions are served in portrait mode and generally deliver higher conversions, you should definitely upload landscape video assets if you want to access YouTube inventory. Here’s a tip – upload your video assets as unlisted on YouTube before using them in your app campaigns for more detailed analytics.

Be sure to design for both sound on and off environments, given that most people watch ads with sound on YouTube but turn off sound on mobile. Lastly, video inventory on Google App campaigns is skippable so you should include the most important information (such as your app icon) within the first 5 seconds.

HTML5 Assets

Optimal number of assets: 20 HTML5 assets, across 300 x 250, 480 x 320 and 320 x 480 sizes

What you should be testing minimally: 1 HTML5 asset in 320 x 480


HTML5 assets provide users with a unique opportunity to get a taste of your app before deciding if they want to download it for themselves. Yet, advertisers launching their first App campaign rarely have the capability to produce enough of them to engage target audiences at scale.

Prioritize the 320 x 480 portrait size first to capture approximately 70% of all impressions, before moving on to square and landscape sizes. We recommend starting off with playables that take around 90 seconds to complete, and testing different lengths from 30-120 seconds thereafter.

Step 3: Select a Campaign Objective to bid for

Google can optimize your bids based on one of the below three available campaign objectives:

  1. App Installs (based on target cost-per-install or CPI)
  2. In-app Actions (based on target cost-per-action or CPA)
  3. Return on Ad Spend (based on target ROAS)

In the earlier phases of creative testing, it is recommended to optimize for app installs first and allow Google’s algorithm to learn and improve before moving on to target more valuable objectives like in-app actions and return on ad spend.

Step 4: Launch your app campaign and wait

Now comes the most difficult part of creative testing – namely waiting.

Upon launching your App campaign, resist the urge to make any tweaks or adjustments as it will affect Google’s machine learning-based optimization. Depending on whether you are running a campaign for Android or iOS apps, it takes two weeks and four weeks respectively before the learning phase is complete and produces conclusive results.

Step 5: Analyze the results

Creative testing would not be complete without a thorough analysis of your results, and it’s time to review your Ad Assets creative report.

There are two sets of information to look at, namely:

  1. Performance grouping
  2. Performance statistics (i.e. clicks, impressions, CTR…)

The performance grouping data shows how often a particular creative asset is selected over other creative assets in the same category, and ranks performance in relative terms as either low, good or best.

It is important to note that performance grouping is relative, meaning it is possible for three assets with minor differences in CVR to be ranked as low, good and best respectively. Lifetime data is also used for comparison, so give your new assets some time before dismissing them.

Similarly, performance statistics are not as straightforward as you think. CVR and CTR numbers are averaged across different placements and do not provide you with complete information at first glance.

You will need to segment the data by networks in order to see how an asset is performing on each available network.

Identifying your best creative concepts

Look out for creative assets with performance grouping of “Best” and produce more variations of the same concept specialized for each network and placement on Google.

Step 6: Rinse and repeat

Creative testing is an ongoing process which requires constant ideation, production, analysis and optimization over months and even years. Each cycle of testing new concepts and producing variations of successful concepts gives you a further edge over your competitors.

Download our FREE Google App Campaign Creative Optimization Guide for more best practices, or reach out to us at experts@creadits.com if you’re looking for a reliable partner to support your creative testing efforts.