For more than a decade, Japanese mobile games studio Cross Field has been delighting fans of casual and hyper casual games, with hits like “Bingo Treasure,” “Hamster Life,” and “Darts Master.” Over time, Cross Field has developed an audience of millions of fans, both in Asia and the US. And throughout the years, the company has relied on both in-app purchases (IAPs) and ads to drive revenue.
To further grow ads revenue, Cross Field looked into the potential to monetize the app launching experience using a new Google AdMob format called app open ads. These ads operate exactly as the name implies. When players launch the app, they’ll see a three-quarter screen ad as the game is loading. Or, if they leave the app and come back later, they’ll see a new ad.
Early trials with app open ads have shown they can boost revenue significantly. Still, developers at the 13-year-old company were hesitant to implement a new ad format in case it lowered retention rates or increased churn. With such intense competition in the casual gaming industry, publishers want to avoid doing anything that might cause them to lose players.
Extensive A/B testing was needed to prove that app open ads could boost revenues without also alienating users. In the end, the company found the right balance for ad display frequency to preserve user retention. By adopting app open ads, Cross Field was able to boost average revenue per user (ARPU) by 30%, with little to no churn.
Finding the right balance between revenue and retention
It's a delicate balancing act for any game publisher. How do you boost ad revenue without disrupting the gaming experience or alienating loyal fans?
"The biggest roadblock was convincing our development team that the new ad placement wouldn't be intrusive to the user experience or lower our reviews on the Play Store," notes Yuki Daigo, Head of Marketing for Cross Field. "We needed to prove to the team that introducing app open ads wouldn't negatively impact retention metrics, while providing a net positive in terms of revenue."
In other words, before the studio was willing to fully commit to the new ad format, extensive testing would be required.
Using A/B testing with different cohorts and ad frequencies
In April 2022, Cross Field began experimenting with app open ads in three of its most popular titles. Using Firebase A/B Testing, it divided the tests into three cohorts, each with different levels of exposure to open app ads.
AdMob open app ads boost ARPU by 30%
The initial results, collected over periods ranging from two weeks to two months, were remarkable. Overall, total ad revenue increased by as much as 70%. Cross Field also observed correlation between retention rate and level of ad exposure. The company found that by adjusting frequency caps to show app open ads 50% of the time, it could achieve the right balance between revenue and retention.
App open ads now represent 20% of all in-app ad revenue in the 18 apps where it has been implemented. Overall, Cross Field has been able to generate an increase in average revenue per user (ARPU) of more than 30% by monetizing the app from the moment a user opens it. "Using Firebase A/B Testing helped us convince our development team that introducing app open ads wouldn't negatively affect retention and churn KPIs," adds Daigo. "Since this is a new ad placement shown between gameplay segments, it allowed us to strike a good balance between user retention and new ad revenue. We are very happy with this outcome."
An AdMob partner since 2013, Cross Field has always shown a willingness to experiment with new platforms and innovative ideas. Its success with the open app ad format, especially with US-based audiences, is inspiring the company to expand its overseas activities.
The revenue impact on apps with users outside Japan was so great that it motivated us to create more apps for the export market," says Daigo. "We're working hard to create an English language version of our popular Mahjong game, which we hope to release before the end of the year.
Head of Marketing, Cross Field,