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SourceMedium supports multiple attribution approaches. This guide explains what we mean by attribution, where it comes from, and which knobs typically cause differences between tools.

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Two common attribution layers

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Last-click attribution (UTM-based)

Last-click attribution assigns credit to the most recent tracked marketing touch before a purchase.
  • Primary inputs: UTM parameters, landing pages, referrers
  • Common use: channel reporting, performance trends, and reconciliation to analytics tools
Related docs:

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Multi-touch attribution (MTA)

Multi-touch attribution assigns credit across multiple touch points within a lookback window.
  • Primary inputs: first-party event streams (e.g., GA4), marketing data, and modeled purchase journeys
  • Common use: understanding incremental contribution across channels, creatives, and landing pages
Related docs:

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Zero-party attribution (survey-based)

Zero-party attribution uses customer-reported survey answers (for example: “How did you hear about us?”) to understand top-of-funnel discovery that tracking often misses. Related docs:

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Common reasons attribution differs between tools

  • Different lookback windows (e.g., 7-day vs 28-day vs 120-day)
  • Missing or inconsistent UTMs (especially for email/SMS and paid social)
  • Cross-domain or checkout tracking limitations
  • Post-purchase edits or delayed revenue recognition
If you’re reconciling against Shopify, start with: Why don’t Executive Summary & Shopify match?