Facebook is still underreporting iOS web conversions, but not as much as before

Facebook estimates that, in aggregate, it is now underreporting iOS web conversions by approximately 8%, down from the 15% in September 2021. The company cited increased adoption of best practices as the main reason for this improvement.

Why we care. While this figure can vary for individual advertisers, 8% is roughly half of 15%, meaning that iOS conversion reporting has gotten a lot better for Facebook advertisers. Still, it’s not completely accurate, which could mean that conversions may be higher than reported for some businesses.

In addition, Facebook expects some degree of underreporting to remain as part of its baseline.

Why Facebook is underreporting. The social media company has cited Apple’s iOS privacy changes as one reason for its diminished reporting capabilities. App Tracking Transparency enables iOS users to request that apps not track their activity, which limits Facebook’s (and other apps’)  ability to track users for advertising purposes.

Facebook has been very vocal about its opposition to Apple’s privacy measures and has even ran full-page newspaper ads against the changes.

Recommendations for better web conversion campaign reporting. For more accurate conversion reporting, Facebook recommends that advertisers running web conversion campaigns:

• Integrate with the Conversions API – This can create a direct connection between your marketing data (from your server, website platform or CRM) and Facebook.
• Verify all domains – This can be especially important for conversions across multiple domains (i.e., websites that use redirectors or geo-redirects).
• Allow enough time before analyzing campaign performance – Due to the nature of delayed data and modeled reporting, Facebook recommends waiting at least 72 hours (or the full length of the optimization window you’ve selected) before evaluating performance.
• Align conversion events with campaign priorities – The order of your events in Event Manager should reflect your priorities (e.g., if purchases are your most valuable goal, ensure that purchases are in the number one position).

Recommendations for better app conversion campaign reporting. For those running app conversion campaigns, Facebook recommends:

• Using a 24-hour conversion window – This helps Facebook’s systems optimize for faster and more predictable feedback cycles.
• Optimizing for your business objective – Miscategorizing your objective can make it more difficult for Facebook to optimize for that objective.