Multi-touch attribution you can audit.

                                  -- MTA Analysis: channel-level first/last/linear attributed revenue

-- Assumptions: timeframe=last_30_days | metric=first_last_linear_revenue_by_marketing_channel | grain=marketing_channel | scope=mta_touch_rows_with_channel_dimension
SELECT
  COALESCE(NULLIF(dimension_value.marketing_channel, ''), '(unknown)') AS marketing_channel,
  COUNT(DISTINCT purchase_order_id) AS journeys,
  SUM(first_touch_revenue_impact.marketing_channel) AS first_touch_revenue,
  SUM(last_touch_revenue_impact.marketing_channel) AS last_touch_revenue,
  SUM(linear_revenue_impact.marketing_channel) AS linear_revenue
FROM `your_project.sm_experimental.obt_purchase_journeys_with_mta_models`
WHERE DATE(purchase_local_datetime) >= DATE_SUB(CURRENT_DATE(), INTERVAL 30 DAY)
  AND dimension_value.marketing_channel IS NOT NULL
GROUP BY 1
HAVING first_touch_revenue > 0 OR last_touch_revenue > 0 OR linear_revenue > 0
ORDER BY linear_revenue DESC
LIMIT 50;