Full Answer

Finding what actually works: Method 1: Backend truth check

• WooCommerce stores customer email, order details
• Match orders to original traffic source (if captured)
• This is ground truth—no attribution model bias Method 2: Coupon code attribution
• Create unique codes per campaign: FACEBOOK25, GOOGLE10
• 100% definitive attribution when used
• Works regardless of tracking status Method 3: BigQuery analysis Method 4: Incrementality testing
• Turn campaign off for geographic or time segment
• Measure difference in conversions
• Proves causation, not just correlation