iOS 17 attribution: what UK ecommerce should do now
iOS 17 attribution: what UK ecommerce should do now
iOS 17 Link Tracking Protection broke another chunk of ecommerce attribution. Here's what UK Shopify brands should measure and how.
What iOS 17 broke
Link Tracking Protection strips known tracking parameters (fbclid, gclid, some UTM permutations) from links opened in Messages, Mail and Safari Private Browsing. Meta and Google both lose visibility on a chunk of iOS conversions.
Impact on UK DTC brands
Meta reports 60-85% of true conversions from iOS. Google's enhanced conversions recover most losses if configured. Klaviyo attribution is unaffected because it uses first-party server-side cookies.
The fixes that matter
- Meta Conversions API (CAPI): server-side event forwarding. Non-negotiable in 2026.
- Google enhanced conversions: hashes first-party data (email, phone) into Google Ads.
- Shopify post-purchase survey: "How did you hear about us?" adds ground-truth attribution.
- UTM discipline: keep utm_source/medium/campaign - Shopify captures these regardless of Link Tracking Protection.
Triangulation, not single-source
Never trust one platform's ROAS in isolation. Compare Meta ROAS + Shopify post-purchase survey + MER trend + Google Analytics 4 - directional agreement is the signal, not one number.
Should UK brands run marketing mix modelling?
Above £2M/year in ad spend, yes. Below that, weekly MER tracking and post-purchase surveys are enough. MMM tools worth evaluating: Prescient AI, Recast, Northbeam.
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Related tools & resources
Free UK ecommerce calculators, definitions and benchmarks referenced in this guide.
Frequently asked questions
Directionally, yes. Absolutely, no. Meta's Aggregated Event Measurement reports 60-85% of true conversions from iOS users. Reconcile with server-side (Conversions API) and Shopify post-purchase surveys.