Your tracking is working. Your attribution data looks great. Your ROAS is 4x. And yet, when you increase the budget, revenue doesn’t move. Attribution tells you who got credit. Incrementality tells you who deserved it. Most WooCommerce store owners have never run that second test — and the tools to do it are free. The … Read more
Your Meta Ads dashboard says 4x ROAS. Your holdout test says 1.8x. Which one do you scale? Reported ROAS on Facebook is proof your pixel fired—not proof your ads drove the sale. With 84% of iOS users opted out of app tracking (Flurry Analytics, 2025) and attribution windows compressed to 7 days post-iOS 14.5, the … Read more
Your retargeting campaign is reporting 8x ROAS. Your store barely broke even last month. According to Cometly’s industry analysis of holdout test results, 75% of conversions credited to retargeting campaigns would have occurred without the ads. Platform attribution doesn’t measure whether your ads caused the sale—it measures whether your ads were nearby when the sale … Read more
Attribution models overestimate channel contribution by 20-40% on average (Gartner, 2025), meaning WooCommerce store owners routinely make budget decisions on inflated numbers. Incrementality testing—comparing a test group exposed to ads against a holdout group that isn’t—reveals which conversions your ads actually caused versus sales that would have happened anyway. Uber famously paused Meta ads for three months, found zero business impact, and reallocated $35 million annually. With Google lowering incrementality test minimums to $5,000 and 52% of brands now using these tests, the gap between attributed sales and incremental sales is becoming impossible to ignore.
Google reduced the minimum spend for incrementality experiments from $100,000 to $5,000 in 2025, making rigorous ad measurement accessible to small WooCommerce stores for the first time. Three practical approaches are now available: platform-native Conversion Lift studies (Google and Meta), DIY geo-holdout tests using existing campaigns, and simple on/off tests any store can run tomorrow. However, 73% of marketing leaders now consider incrementality testing essential (Gartner, 2025), yet none of the popular guides address a critical prerequisite—if 31.5% of visitors are invisible to browser-based tracking, both test and control groups measure incomplete data. Server-side tracking must close this gap before any incrementality experiment can produce trustworthy results.
