From SKAdNetwork (SKAN) to AdAttributionKit (AAK): 7 tips for Apple iOS in-app advertising success

For mobile app marketers, navigating Apple's evolving measurement framework can feel like a moving target. 

SKAdNetwork (SKAN), the company’s privacy-centric API for campaign analytics, has undergone several updates, with SKAN 4.0 bringing more granular lifetime value (LTV) measurement and web-to-app attribution. But with Apple's recent announcement of AdAttributionKit (AAK) — expected to build on SKAN’s foundation, with cross-store insights and targeted re-engagement — the landscape is set to evolve further. 

While the full impact of AAK remains to be seen, SKAN continues to play a critical role in driving accurate measurement and optimization for mobile app marketers. As we prepare for more changes to come, let’s revisit the fundamentals of SKAN to ensure a solid foundation for the next phase of iOS attribution.

SKAN fundamentals: Understanding the key concepts

Since the introduction of SKAN in 2021, Apple has released several versions with new features and improvements:

• SKAN 2.0: Introduced conversion values, allowing marketers to receive more granular data about post-install events.
• SKAN 2.2: Added support for view-through attribution, expanding measurement capabilities beyond click-based installs.
• SKAN 3.0: Introduced the 'did-win' parameter for multi-touch attribution, providing insights into ad networks that influenced but didn't win the final attribution.
• SKAN 4.0: The most significant update, bringing hierarchical source identifiers, coarse conversion values, multiple postbacks, and web-to-app attribution.

There are a few foundational privacy mechanisms that make SKAN work: 

• Postback delay: A postback is a string of event data between ad servers that connects ad exposures with conversion events (e.g. app download, in-app purchase). A postback delay, often up to 72 hours for version 4.0, helps ensure user anonymity.
• Crowd anonymity: Insights for mobile app marketers are based on a series of tiered privacy thresholds, corresponding to the number of installs, to prevent user identification. As more installs are delivered, more granular performance data becomes available.

SKAN offers a distinct but complementary attribution framework to those offered by mobile measurement partners (MMPs). While SKAN's attribution window is determined by ad type — with StoreKit Rendered Ads receiving a generous 30-day lookback and a 24-hour lookback for non-StoreKit Rendered ads — probabilistic attributions by MMPs typically offer a 7-day window for click-through and 24-hour for view-through attributions. 

Remember: SKAN and MMPs aren’t mutually exclusive. In fact, a single app install can be simultaneously attributed by both SKAN and an MMP, providing a more comprehensive view of campaign performance.

What every marketer should know about SKAN

While privacy frameworks like SKAN (and the coming AAK) can be complex to navigate, following certain guidelines will improve your campaign performance. These best practices are designed to ensure you’re optimizing for iOS’ unique mobile ad attribution and adapting to its evolving features.

1. Consolidate small campaigns into high-volume ones

SKAN's privacy threshold, or “crowd anonymity,” mechanism can significantly impact small campaigns. This protocol will send “NULL” conversion values until app install postbacks surpass a given threshold. To mitigate this:

• Combine smaller campaigns: Merging low-volume campaigns into larger ones helps surpass the privacy threshold more consistently, providing more data.
• Aim for 20-25 installs per day: This is crucial for minimizing NULL conversion values. Achieve this on a per-app, per-SKAN campaign ID, and per-SKAN version group basis.
• Balance granularity and volume: While consolidation is important, find a balance that provides enough data for optimization without losing critical audience segmentation.

By consolidating campaigns, you increase the likelihood of receiving valuable conversion data, enabling better optimization and return on ad spend.

2. Account for postback delays when changing budgets

Built-in postback delays can complicate budget management, especially with SKAN 4.0.

• Anticipate delayed effects: Budget changes won't immediately reflect in SKAN metrics due to the postback delay. Expect to see the impact in roughly 2 to 4 days.
• Use a 72-hour lookback window: Since data can delay, wait at least 72 hours before reviewing campaign metrics. This window accounts for the random delay in SKAN or AAK postbacks, and ensures a sufficient dataset for analysis.
• Be cautious with budget decreases: Reducing your budget might lead to deterioration in cost per action (CPA); this stems from increases in NULL values caused by the privacy threshold's impact.

When adjusting spend, consider making smaller, incremental changes rather than large shifts. This measured approach will help you better assess the impact of each change.

3. Share full event-level data, including unattributed data

To maximize ad performance, mobile marketers should gather as much data as possible. Ads partners like Moloco use machine learning (ML) models to predict user conversion, and both attributed and unattributed data are vital training samples, leading to more effective campaigns and better user experiences. 

Providing comprehensive data for ML models can help: 

• Enable more accurate predictions: ML models can make real-time adjustments based on all users, not just those with attributed conversions.
• Drive more efficient conversions: Models can begin training on your data before campaigns start, accelerating your time to value with faster optimization and higher click rates. 
• Get granular while protecting privacy: Unattributed data can fill in gaps where fragmented SKAN postbacks limit the granularity and accuracy of data for ML model training.

4. Enable StoreKit-rendered Ads

Storekit is the simple and secure framework for in-app purchases of digital goods or services across all Apple platforms. StoreKit-rendered ads are an extension of Apple’s App Store; these creative elements offer improved UX by allowing users to seamlessly download a promoted app without leaving the current in-app experience. 

StoreKit-rendered ads offer significant benefits within the SKAN framework:

• 'Store Page Pop-up' and 'SKOverlay': Full-screen interstitial and banner overlay StoreKit ads, respectively, that are broadly used across in-app interstitial inventory
• Extended attribution windows: StoreKit-rendered ads have a default 30-day lookback window, compared to the standard 24-hour window for view-through ad attribution.
• Higher SKAN performance: Internal data suggests that SKOverlay can increase SKAN-reported installs by up to 30%, while Store Page Pop-up provides an additional 10% lift.

StoreKit ads are an important piece of any SKAN marketing strategy. Use these compatible ad formats in your campaigns to maximize your opportunity for rich-media ad rendering and longer lookback windows.

5. Exclude lower SKAN versions and non-attributable traffic

Not all SKAN traffic is created equal. To optimize your campaigns:

• Deactivate older SKAN versions: As of February 2024, 94% of in-app inventory supports SKAN 3.0 and 4.0, which offer enhanced features for deeper insights and better optimization. Focusing your campaigns on these versions helps unlock richer performance data and more efficient results compared to older versions.
• Disable SKAN non-attributable traffic: Consider deactivating any traffic that cannot be measured, ensuring that budgets are spent more efficiently and with the ability to learn and optimize. In Moloco’s ad platform, marketers can configure this step with a simple on/off toggle.

By concentrating your mobile ad budgets on the most effective iOS traffic, you're positioning each campaign to drive a higher number of installs and potentially lower acquisition costs. 

6. Migrate to SKAN 4.0 conversion value mapping

With the new hierarchical structure in SKAN 4.0, revisit your conversion value mapping to ensure you're capturing the most valuable user actions. SKAN 4.0 allows for up to three postbacks, including new features such as:

• Coarse conversion values: Gain long-term conversion data using the new Low, Medium, and High coarse values for the second and third postbacks.
• Flexible locking windows: Determine whether to use lock windows based on your measurement partner's advice. Generally, locking on the key performance indicator (KPI) event rather than time is recommended.
• Detailed industry guides: Familiarize yourself with the latest SKAN 4.0 configuration options provided by your MMP, such as AppsFlyer, Adjust, Singular, Branch, Kochava. 

By adopting SKAN 4.0's enhanced features, you can gain more granular insights into user behavior over extended periods, improving the accuracy of your lifetime acquisition models.

7. Boost user ATT opt-in rates

Increasing the number of users who opt-in to App Tracking Transparency (ATT) can significantly enhance your targeting capabilities.

• Display the ATT prompt strategically: Consider presenting it on the first app launch, which typically yields higher opt-in rates.
• Use user-focused language: Emphasize the benefits of opting in, such as personalized experiences or supporting free content. Be transparent about how user data will be used and protected.
• Test different approaches: Continuously experiment with various strategies to improve opt-in rates. This might include different messaging, timing, or even user interface designs for the prompt.

Remember, data from opted-in users serves as vital user-level training data for more accurate ad targeting, complimenting your SKAN efforts.

Building your SKAN action plan

As Apple continues to refine its privacy-preserving attribution methods, staying updated on these changes is crucial for marketers. With Apple's Attribution Kit (AAK) on the horizon — building on SKAN’s privacy-first framework — the fundamentals of SKAN remain essential for driving success on iOS, and we will continue to update these best practices as we observe AAK adoption and other future developments.

Stay ahead of the curve with Moloco, helping over 3 million mobile app owners grow their businesses by leveraging SKAN today and preparing for tomorrow's innovations.