Complete Guide to ROAS & Ad Tracking Issues
Why ROAS doesn't match reality, how broken attribution ruins your campaigns, and exactly how to fix ad tracking.
Common ROAS Tracking Problems
- Meta Ads ROAS is 5x but you're barely breaking even
- Google Ads shows conversions Shopify never recorded
- Campaign ROAS numbers change dramatically day-to-day
- You can't tell which campaigns are actually profitable
- Attribution gives credit to the wrong campaigns
- Conversion values don't match actual order totals
Why ROAS Numbers Are Wrong
Your ad platform shows one ROAS, but your actual profit is completely different. This happens because the conversion data your ads receive is broken. The three main culprits:
- Duplicate conversions: If your pixel or GA4 tag fires twice on every purchase, Meta and Google think you got 2x the sales you actually did. Your ROAS looks amazing—5x, 8x, 10x—but you're actually losing money on every order because the data is fake.
- Wrong conversion values: Your pixel sends the wrong amount. Maybe it's sending subtotal instead of order total (missing tax and shipping), or a hardcoded test value like "10", or pulling the wrong variable from your data layer. Either way, the revenue numbers in your ad account don't match reality.
- Attribution problems: The wrong campaign gets credit for the sale. Someone clicks a Facebook ad, then Googles your brand and buys. Meta claims the conversion, Google claims it too, and you think both campaigns are profitable when really you just paid twice for one customer.
How to Fix ROAS Tracking
Step 1: Fix Duplicate Conversions
Use Meta Pixel Helper and Tag Assistant to check if events fire multiple times. If you see "Purchase - 2 events" or GA4 showing 2x the conversions you actually have, you have duplicates. Find all pixel and GA4 installations (theme code, GTM, apps) and remove duplicates. Keep one clean installation through GTM.
Step 2: Verify Conversion Values
Complete a test order on your site. Note the exact order total. Then check Meta Events Manager and GA4 to see what conversion value was recorded. Do they match? If not, your pixel or GA4 tag is pulling the wrong variable.
Fix it by updating your GTM tag to pull the correct value from your ecommerce data layer. The value should be order total (subtotal + tax + shipping) in the correct currency. Never hardcode values.
Step 3: Understand Attribution Windows
Meta uses a 7-day click or 1-day view attribution window by default. That means if someone clicks your ad and buys within 7 days, Meta gets credit—even if they Googled your brand and came back directly. Google Ads uses last-click attribution by default. This causes overlap: both platforms claim credit for the same sale.
You can't fully fix attribution overlap, but you can reduce it by using custom attribution windows and understanding your true blended ROAS (total revenue / total ad spend across all channels). Don't judge individual campaigns in isolation.
Step 4: Set Up Conversion Value Rules
For more accurate profitability tracking, subtract costs from your conversion value. If your average order value is £100 but your product cost + shipping is £60, send a value of £40 to your ads. This way, your ROAS reflects actual profit, not just revenue.
Why Campaigns Get Wrong Attribution
Attribution is messy because customers don't follow linear paths. They might:
- Click a Facebook ad, then Google your brand later and buy
- See a YouTube ad, then click a Google Shopping ad and purchase
- Click your ad 3 times over a week before buying
Each ad platform uses its own attribution model and claims credit differently. Meta uses probabilistic modeling to estimate conversions it can't directly track (especially post-iOS 14). Google Ads uses data-driven attribution for Search campaigns. Neither is 100% accurate.
The fix: Track blended ROAS at the account level. Total revenue / total ad spend across all platforms = your real ROAS. Use platform-specific ROAS as directional signals, not absolute truth.