There’s a trap that UA managers for IAA games — games that monetize through ad revenue — fall into more often than they realize.
Treating installs and ad impressions as the same metric.
When a campaign is run on CPI, “installed user” and “user who watches ads” get conflated. But CPI is a model where advertisers pay for every installation, while CPE campaigns incentivize in-app engagement — which measurably improves user retention, especially when compared against CPI or CPC campaigns. (AppsFlyer Glossary)
For IAA games, the real value isn’t the install itself. It’s how long, and how often, a user stays.
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Playtime Is the Signal That Matters
When designing CPE events for IAA games, the most powerful trigger is playtime.
Rewarded playtime models — pioneered by platforms like adjoe — pay users for time spent in-app rather than for installs or simple task completion. adjoe Playtime helps achieve target ROAS, improved LTV, and higher retention rates. App developers are significantly adopting rewarded UA platforms over traditional UA — in a 2025 survey, 82% of mobile game developers say reward-based user acquisition outperformed traditional UA. (adjoe, 2026)
A real campaign proves this. After launching a rewarded playtime campaign, the puzzle game Zen Life saw ROAS increase by 125%, with IAP revenue growing an additional 15% — on top of existing ad revenue. (AppSamurai, 2025)
A rewarded playtime campaign drove a 125% ROAS increase and 15% IAP growth
Playtime rewards deliver on their promise. A structure that rewards users for time spent increases both session length and retention. It gives non-spenders value too, deepening their attachment to the game, and creates natural moments to introduce IAP — like unlocking special items after a long session. (AppSamurai, 2025)
The Rise of Hybrid Casual
IAA alone is no longer enough.
Combining in-app purchases (IAP) with in-app advertising (IAA) consistently yields better financial outcomes than either model alone. For Android mid-core games, a hybrid model achieves 146% ROAS by Day 90 — significantly outperforming IAP-only (93%) and IAA-only (58%) models. (AppSamurai, 2025)
Hybrid monetization outperforms single-model approaches by Day 90
What this means is simple. If you design your campaign around ad revenue alone, you’re seeing less than half of what the game can actually generate.
What Should the CPE Trigger Be?
For IAA and hybrid casual games, CPE conversion points generally fall into three categories.
Playtime-based — simple but powerful, like “30+ minutes played.” Directly correlates with ad impressions, easy to measure, and relatively fraud-resistant.
Session-based — sets retention itself as the conversion point, like “log in 3 days in a row.” Since ad revenue scales with cumulative sessions, session count becomes a proxy for ad revenue contribution.
Progression-based (hybrid) — combines IAP potential and IAA contribution in one condition, like “reach level X and watch N ads.” Particularly well-suited for hybrid casual games.
Playtime events combine time-based rewards with in-game milestone-based rewards, resulting in deeper engagement, increased spend, and ultimately higher LTV. (Mistplay, 2025)
Choosing the right CPE trigger depends on what signal you’re trying to buy
| Trigger type | Example | Measurability | Fraud resistance | LTV signal |
|---|---|---|---|---|
| Playtime-based | 30+ minutes played | High | High | Moderate |
| Session-based | Login 3 days in a row | Moderate | Moderate | High |
| Progression-based (hybrid) | Reach level X + watch N ads | Moderate | High | High |
Sources: adjoe 2026 · Mistplay 2025 · AppSamurai 2025
Closing: Pay for the User Who Stayed, Not the One Who Watched
IAA UA has long been judged by one question: how many installs did we drive?
But ad revenue doesn’t come from installs. It comes from time spent.
Sensor Tower’s 2025 analysis shows that CPI campaigns have a 35% lower retention rate than CPE-based models. AppsFlyer’s 2024 Performance Index found that CPE models outperform CPI by 22% in retention and lifetime value. (AdBreak Media, 2025)
Don’t pay for the ad that was watched. Pay for the behavior that made someone stay.
