Question

How do you reconcile conversion data discrepancies between Facebook Ads Manager (using a 7-day click + 1-day view attribution) and GA4’s data-driven attribution model, especially in iOS-heavy campaigns post-ATT framework?

Answer 1

Discrepancies between Facebook and your backend (e.g., Shopify, CRM, GA4) are common and usually caused by:

Key Reasons:

• Attribution windows differ: Facebook defaults to a 7-day click / 1-day view, while your backend uses last-click or real-time attribution.

• Cross-device activity: Users may click an ad on one device (e.g., mobile) and convert later on another, causing tracking gaps.

• Privacy restrictions: iOS updates, ad blockers, and cookie consent banners can block tracking (especially Meta Pixel).

• Event duplication or missing events: If your Pixel and CAPI aren’t deduplicated properly, Meta may drop events or double count them.

How to Reconcile:

• Use UTM parameters to track Facebook traffic in Google Analytics or backend tools.

• Align your attribution windows as closely as possible across platforms.

• Check Meta Events Manager to confirm pixel and server events are firing and properly deduplicated.

• Use GA4 DebugView or custom reports to compare the same conversions across both platforms for the same time window.