Attribution Windows
Attribution windows decide which conversions get credited to which ad click or view. Here's how the 1-, 7- and 28-day settings differ — and why shrinking windows after iOS14 made ROAS look worse without performance actually dropping.
Attribution Windows
The time period after an ad click or view in which a resulting conversion is credited back to that ad.
An attribution window is the lookback period an ad platform uses to connect a conversion (purchase, signup, add-to-cart) back to a prior ad interaction. The three windows you'll see most often are 1-day, 7-day, and 28-day, each available in click-through and view-through flavors.
The window you choose doesn't change what actually happened on your store — it changes which conversions the platform claims credit for in its reports. That's why two managers looking at the same Meta account can see very different ROAS numbers: they're reading different windows. Since Apple's iOS14 ATT prompt rolled out in 2021, the default windows tightened, which mechanically lowered reported ROAS for most advertisers.
Every paid platform — Meta, Google, TikTok, Pinterest — has its own attribution window settings, and they don't agree. Meta's default is now 7-day click + 1-day view. Google Ads defaults to data-driven attribution with a 30-day click window. TikTok defaults to 7-day click + 1-day view. The same purchase can be credited to two platforms simultaneously, which is why the sum of platform-reported revenue almost always exceeds Shopify's actual order total.
Click-through attribution counts a conversion when someone clicks an ad and converts within the window. View-through counts a conversion when someone simply sees the ad (no click) and converts later. View-through is generous to the platform — it's the setting most likely to inflate reported ROAS, especially on Meta where impressions are cheap and frequent.
Reported ROAS (window) = Conversions credited within window × AOV ÷ Ad spend
Conversions credited within window
Windowed conversions
Purchases the platform attributes to ad clicks/views that occurred within the selected lookback period.
AOV
Average order value
Average revenue per attributed order in the same period.
Ad spend
Ad spend
Total platform spend in the reporting period.
A Shopify apparel store spends €20,000 on Meta in a month. AOV is €80. Under 7-day click + 1-day view, Meta credits 350 purchases. Under 1-day click only, Meta credits 210 purchases.
Ad spend: €20,000
AOV: €80
7d click / 1d view conversions: 350
1d click conversions: 210
→ 7d/1d ROAS = (350 × 80) / 20,000 = 1.40x. 1d click ROAS = (210 × 80) / 20,000 = 0.84x.
Same campaign, same spend, same actual sales — the reported ROAS swings 67% based on the window. Neither number is wrong; they're answering different questions about the same activity.
The iOS14 ATT rollout in April 2021 forced Meta and other ad platforms to deprecate the old 28-day click default. Most ad accounts saw reported ROAS drop 20-40% overnight when the window shrank to 7-day click. Actual store revenue didn't move much — only what Meta was allowed to claim. This is the single biggest source of confusion when reading paid reports against Shopify GMV today.
Typical share of attributed conversions by window, by channel
| Channel | 1-day click | 7-day click | 28-day click | View-through (1d) |
|---|---|---|---|---|
| Meta (prospecting) | 55% | 85% | n/a (deprecated) | 10-15% |
| Meta (retargeting) | 70% | 92% | n/a | 5-8% |
| Google Search (brand) | 90% | 97% | 99% | negligible |
| Google Search (non-brand) | 65% | 85% | 92% | negligible |
| TikTok Ads | 45% | 80% | n/a | 10-20% |
| 35% | 70% | 85% | 5-10% |
Read the table this way: on Meta prospecting, only 55% of attributed conversions happen within 24 hours of the click — the other 45% need a longer window to be counted at all. That's why switching from 7-day click to 1-day click on a top-of-funnel campaign can make it look like it stopped working. The fix is consistency: pick one window per channel, document it, and compare against Shopify's actual order data using a marketing-mix or incrementality lens rather than platform-reported ROAS alone.
Attribution windows: common questions
Meta's default since iOS14 is 7-day click plus 1-day view. The old 28-day click and 28-day view options were deprecated in 2021 and are no longer selectable on most accounts.
Most performance managers use 7-day click as the primary read because it captures the natural consideration window for fashion, beauty and homeware purchases. Use 1-day click as a directional sanity check, not as your optimization target.
Because the maximum window shrank from 28-day click + 1-day view to 7-day click + 1-day view, and SKAdNetwork made view-through tracking less reliable. Meta simply got credit for fewer conversions. This is covered in detail in our iOS14 ROAS impact breakdown.
Click-through credits a conversion when the user clicked the ad before converting. View-through credits the conversion if the user merely saw the ad (an impression) without clicking. View-through is more generous and tends to inflate ROAS on high-impression channels like Meta.
No. Google Ads defaults to data-driven attribution across a 30-day click window for most conversion actions, and it doesn't expose view-through on Search at all. Comparing Meta's 7-day click ROAS to Google's 30-day click ROAS is apples to oranges.
Because every platform claims overlapping credit within its own window. A single €100 order can show up in Meta, Google, and Klaviyo reports all at once. Always reconcile to Shopify as the source of truth before judging channel performance.
Attribution windows describe what the platform claims; incrementality describes what the channel actually caused. A campaign can show strong 7-day click ROAS while contributing zero incremental revenue. See attribution and incrementality for how the two fit together.
On Meta you can pivot historical data across the windows the platform still supports (1d click, 7d click, 1d view) using the comparison columns. You cannot recover the deprecated 28-day click data — it's gone.
Pick one window per channel and stick with it for at least a quarter. For most Shopify stores in the €1M-€15M band, 7-day click on Meta and 30-day click on Google Ads are the common defaults, validated against blended ROAS (total revenue ÷ total ad spend).
Directionally yes, but the share of late conversions is even higher on those channels because their audiences tend to convert further from the click. Using only 1-day click on TikTok will systematically undercount its contribution.
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