Question 1

What is the iOS attribution gap?

Accepted Answer

After Apple's App Tracking Transparency rolled out in 2021, ad platforms lost the ability to track most iOS users across apps and sites. Meta and Google now under-report conversions because they can only count what they can see — typically 60–80% of actual conversions. The 'gap' is the difference between what they report and what your shop actually saw.

Question 2

How do I know my server conversion number?

Accepted Answer

Pull it from your source of truth — Shopify Analytics, GA4, or your data warehouse — for the same campaign window and audience scope you're comparing. Filter by the channel (e.g. Meta-attributed via UTM or last non-direct click) so you're comparing apples to apples. Don't compare Meta's view-through conversions to GA4's last-click — they answer different questions.

Question 3

What's a normal gap percentage?

Accepted Answer

Post-iOS, a 20–35% gap on Meta is the new normal even with Conversions API and proper deduplication. Under 10% means your CAPI / sCAPI / GA4 setup is excellent. Over 35% suggests broken pixel firing, bad event match quality, or duplicate conversion setups — audit Events Manager and your Pixel Helper output.

Question 4

How should I bid given the gap?

Accepted Answer

Bid in-platform against an adjusted target. If your true CPA target is $40 and Meta only sees 70% of conversions, your in-platform target should be $40 × 0.70 = $28. Otherwise the platform optimizer thinks you're wildly unprofitable and throttles delivery. This calculator gives you that adjusted number directly.

Question 5

Will iOS attribution get worse?

Accepted Answer

Probably yes. Apple keeps tightening signal — Mail Privacy Protection, Hide My Email, and more recently Advanced Data Protection compound the problem. Brands that win in this environment lean harder on first-party data (email lists, on-site events, post-purchase surveys) and creative quality. Better creative beats better attribution every time.

iOS Attribution Gap Calculator

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