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First Touch Channel Grouping

Also known as: First-Touch Channel, Original Acquisition Channel, Acquisition Channel Grouping

AcquisitiondimensionE-commerce: Top-of-Funnel & Marketing AcquisitionE-commerce

The default channel grouping of the earliest recorded session for a user within the attribution lookback window, persisted at user level so that every later event, order and revenue amount can be attributed back to how that customer was originally acquired. It is the backbone dimension for first-touch acquisition reporting and for separating marketing-sourced growth from organic and direct demand.

Business Use Case

Marketing leadership breaks down new customers, first-order revenue and 90-day repeat rate by this dimension to decide which acquisition channels deserve incremental budget, and the finance team uses it to reconcile channel-level customer acquisition cost against channel-level lifetime value.

Business Criticality

High

Journey / Navigation Area

Discovery

Owning Function

Marketing

Scope

User

Calculation Notes

1️⃣ Derived once per user from the first session_start event inside a rolling 90-day lookback that precedes the user's first conversion; it is never re-evaluated after the first purchase. 2️⃣ Values follow the GA4 default channel grouping taxonomy: Direct, Organic Search, Paid Search, Paid Social, Organic Social, Display, Affiliate, Email, SMS, Referral, Organic Video, Paid Video, Cross-network, Unassigned. 3️⃣ Sessions expire after 30 minutes of inactivity; a session that spans midnight is not treated as a new first touch. 4️⃣ When user_id stitching later links an anonymous device to a known customer, the earliest touch across all stitched identities wins. 5️⃣ Internal traffic, known bots and test orders are excluded before the first session is selected. 6️⃣ Sessions with (not set) source and medium are grouped as Unassigned rather than dropped, so denominators stay complete.

Technical Details

Data Typestring
Lookback WindowUser

Events

PlatformEvent
Google Analytics 4session_start
AdobeSession Start

Data Mappings

W3 Data Layer
{
  "digitalData": {
    "user": [
      {
        "profile": [
          {
            "profileInfo": {
              "profileID": "<pseudonymous_user_id>"
            },
            "attributes": {
              "firstTouchChannelGrouping": "<channel_grouping>"
            }
          }
        ]
      }
    ],
    "page": {
      "pageInfo": {
        "referringURL": "<referrer>"
      },
      "attributes": {
        "campaignSource": "<utm_source>",
        "campaignMedium": "<utm_medium>",
        "campaignName": "<utm_campaign>"
      }
    }
  }
}
GA4 Data Layer
{
  "event": "session_start",
  "user_id": "<pseudonymous_user_id>",
  "first_touch_channel_grouping": "<channel_grouping>",
  "source": "<utm_source>",
  "medium": "<utm_medium>",
  "campaign": "<utm_campaign>",
  "landing_page": "<landing_page_path>"
}
Adobe Client Data Layer
{
  "event": "session_start",
  "eventInfo": {
    "eventName": "Session Start"
  },
  "user": {
    "firstTouchChannelGrouping": "<channel_grouping>"
  },
  "marketing": {
    "source": "<utm_source>",
    "medium": "<utm_medium>",
    "campaign": "<utm_campaign>"
  },
  "page": {
    "landingPage": "<landing_page_path>",
    "referrer": "<referrer>"
  }
}
XDM Mapping
{
  "eventType": "web.webinteraction.linkClicks",
  "channel": {
    "_id": "https://ns.adobe.com/xdm/channels/web",
    "typeAtSource": "<channel_grouping>"
  },
  "marketing": {
    "trackingCode": "<utm_campaign>"
  },
  "_experience": {
    "analytics": {
      "customDimensions": {
        "eVars": {
          "eVar12": "<first_touch_channel_grouping>"
        }
      }
    }
  }
}

SQL Queries

Google Analytics 4 (BigQuery)
-- ==========================================
-- 1. GOOGLE BIGQUERY SQL
-- ==========================================
WITH channel AS (
  SELECT
    user_pseudo_id,
    event_timestamp,
    LOWER(COALESCE(traffic_source.source, '(direct)')) AS source,
    LOWER(COALESCE(traffic_source.medium, '(none)')) AS medium,
    CASE
      WHEN COALESCE(traffic_source.source, '(direct)') = '(direct)' AND COALESCE(traffic_source.medium, '(none)') IN ('(none)', '(not set)') THEN 'Direct'
      WHEN LOWER(traffic_source.medium) = 'organic' THEN 'Organic Search'
      WHEN LOWER(traffic_source.medium) IN ('cpc', 'ppc', 'paidsearch') THEN 'Paid Search'
      WHEN LOWER(traffic_source.medium) IN ('paidsocial', 'paid_social', 'paid-social') THEN 'Paid Social'
      WHEN LOWER(traffic_source.medium) IN ('social', 'social-network', 'social-media', 'sm') THEN 'Organic Social'
      WHEN LOWER(traffic_source.medium) IN ('display', 'cpm', 'banner') THEN 'Display'
      WHEN LOWER(traffic_source.medium) = 'affiliate' THEN 'Affiliate'
      WHEN LOWER(traffic_source.medium) IN ('email', 'e-mail', 'e_mail') THEN 'Email'
      WHEN LOWER(traffic_source.medium) = 'sms' THEN 'SMS'
      WHEN LOWER(traffic_source.medium) = 'referral' THEN 'Referral'
      ELSE 'Unassigned'
    END AS channel_grouping
  FROM `your-project.analytics_123456789.events_*`
  WHERE event_name = 'session_start'
    AND _TABLE_SUFFIX BETWEEN FORMAT_DATE('%Y%m%d', DATE_SUB(@report_start, INTERVAL 90 DAY)) AND FORMAT_DATE('%Y%m%d', @report_end)
),
first_touch AS (
  SELECT
    user_pseudo_id,
    ARRAY_AGG(STRUCT(channel_grouping, source, medium) ORDER BY event_timestamp ASC LIMIT 1)[OFFSET(0)] AS ft
  FROM channel
  GROUP BY user_pseudo_id
)
SELECT
  user_pseudo_id,
  ft.channel_grouping AS first_touch_channel_grouping,
  ft.source AS first_touch_source,
  ft.medium AS first_touch_medium
FROM first_touch;
Adobe Experience Platform (AEP Query Service)
-- ==========================================
-- 2. ADOBE AEP QUERY SERVICE SQL
-- ==========================================
WITH channel AS (
  SELECT
    endUserIDs._experience.mcid.id AS user_id,
    timestamp,
    LOWER(COALESCE(marketing.trackingCode, 'direct')) AS tracking_code,
    CASE
      WHEN marketing.trackingCode IS NULL AND web.webReferrer.URL IS NULL THEN 'Direct'
      WHEN LOWER(marketing.trackingCode) LIKE '%organic%' THEN 'Organic Search'
      WHEN LOWER(marketing.trackingCode) LIKE '%cpc%' OR LOWER(marketing.trackingCode) LIKE '%paidsearch%' THEN 'Paid Search'
      WHEN LOWER(marketing.trackingCode) LIKE '%paidsocial%' THEN 'Paid Social'
      WHEN LOWER(marketing.trackingCode) LIKE '%social%' THEN 'Organic Social'
      WHEN LOWER(marketing.trackingCode) LIKE '%display%' THEN 'Display'
      WHEN LOWER(marketing.trackingCode) LIKE '%affiliate%' THEN 'Affiliate'
      WHEN LOWER(marketing.trackingCode) LIKE '%email%' THEN 'Email'
      WHEN LOWER(marketing.trackingCode) LIKE '%sms%' THEN 'SMS'
      WHEN web.webReferrer.URL IS NOT NULL THEN 'Referral'
      ELSE 'Unassigned'
    END AS channel_grouping
  FROM web_experience_events
  WHERE eventType = 'web.webpagedetails.pageViews'
    AND timestamp >= DATE_SUB(CAST(@report_start AS DATE), INTERVAL 90 DAY)
    AND timestamp < DATE_ADD(CAST(@report_end AS DATE), INTERVAL 1 DAY)
),
ranked AS (
  SELECT
    user_id,
    channel_grouping,
    tracking_code,
    ROW_NUMBER() OVER (PARTITION BY user_id ORDER BY timestamp ASC) AS rn
  FROM channel
)
SELECT
  user_id,
  channel_grouping AS first_touch_channel_grouping,
  tracking_code AS first_touch_tracking_code
FROM ranked
WHERE rn = 1;

Source Data

Digital Analytics (GA4) stitched with CRM customer identity (Salesforce)

Dependencies

[ "session-start", "traffic-source-medium", "user-id", "campaign-name" ]

Report Attributes

Purchase Date New vs Returning Customer Country Device Category Campaign Name Landing Page Product Category of First Order

Segment Eligibility

true

Governance

Data SensitivityInternal

Derived Dimensions

first-touch-marketing-flagfirst-touch-paid-vs-owned

Governance

Created bydevyendarm
Created on9/9/2026
Last modified bydevyendarm
Last modified on9/9/2026
Version1.0.0
Validation stateqa passed
StatusPUBLISHED

GitHub

View related Pull Requestcatalog/dimensions/first-touch-channel-grouping.yml

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