In digital advertising—especially when using Demand‑Side Platforms (DSPs)—many marketers rely heavily on Return on Ad Spend (ROAS) as their primary performance metric. While ROAS offers a straightforward snapshot into spend efficiencies, optimizing solely for installs or early revenue signals can overlook long-term user value, erode profitability, and foster short-sighted campaigns.
1. Beyond Installs: The Limitations of ROAS
DSPs often prioritize metrics like cost per install (CPI) or immediate ROAS, which can yield large volumes of users but not necessarily ones that generate meaningful engagement or long-term spending. For example, optimizing solely on Day‑7 ROAS (D7 ROAS) may not reflect true lifetime value, because cohorts often diverge significantly after week one. The red cohort in Liftoff’s analysis may outperform early on, but fall off sharply by Day 60 compared to a cohort with steadier long-term behavior.
2. In-App Events & LTV-Driven Optimization
To build sustainable growth, top-tier DSPs now offer event-based bidding and cohort-level optimization:
- In‑app events: These include purchases, ad interactions, subscription sign‑ups, or milestones—signals that drive true engagement. Liftoff, for instance, enables bidding on both in‑app purchase (IAP) and in‑app ad revenue (IAA) events.
- With IAA optimization, advertisers saw average 11% ROAS lifts and 22% lower CPI by targeting users likely to view ads, not just make purchases.
This multi-event strategy builds a more robust user foundation rather than relying on a single KPI.
3. Cohort-Based Analysis: Profiling True Value
Cohorts—groups of users acquired in the same timeframe—can exhibit dramatically different revenue curves. One cohort may display high early spending but fall off quickly; another may grow steadily over time.
Using cohort-based ROAS enables nuanced bid multipliers and more intelligent media spend allocation. However, as Liftoff warns, relying only on simple multipliers across channels can result in wasted budget or missed opportunities. Sophisticated platforms are building machine learning models that digest per-cohort behavior, in-app engagement, and platform signals to bid more intelligently.
4. DSPs That Offer Event-Based Buying
Two DSPs leading this charge are Liftoff and InMobi.
- Liftoff integrates multi-event bidding that spans IAP, IAA, and hybrid revenue models. Its Accelerate suite sends postbacks for key events and uses ML models to drive both purchases and ad impressions.
- InMobi DSP, across its global exchange network, offers flexible in-app performance buying tied to CPI and event-driven goals. Though details on user-level bidding are lighter, InMobi emphasizes programmatic reach and data-rich audience segmentation.
Other DSPs, such as The Trade Desk or MediaMath, offer similar capabilities, but the depth of event-layered campaign optimization varies. The key differentiator for Liftoff and InMobi is their unified postback handling of diverse in‑app user events, enabling cleaner signals into bidding models.
5. Tips for Smarter KPI Strategy
| Tip | Description |
| Define core events early | Establish which post-install events matter: sign-up, tutorial complete, first spend, subscription, specific milestone, or ad engagement. |
| Leverage cohort insight | Analyze how early behavior predicts future lifetime value (LTV)—set distinct targets per channel, country, and operating system (OS). |
| Use event-based bid signals | If your DSP supports it, configure bids on early post-install events, not just install or revenue. |
| Combine events | Chase a mix: e.g., users likely to both spend and view ads, for multi-revenue coherence. |
In Summary
Focusing solely on ROAS—especially early ROAS—can obscure the user behaviors that drive true profitability. The future of DSP ad buying lies in event-based optimization and cohort modeling, where in‑app events and long-term LTV shape bidding decisions. Platforms like Liftoff and InMobi are pioneering this shift, building campaigns around hybrid signals—purchases, ad interactions, and cohorts—to drive sustainable user acquisition that aligns with real business value.
When ROAS becomes just one signal in a broader tapestry of KPIs, marketers can build campaigns that not only scale but endure.