Attribution window

An attribution window is the time horizon during which an ad platform will credit a conversion to a prior ad interaction. If you click an ad on Monday and buy on Wednesday, a 7-day click window credits the conversion to that ad. A 1-day window doesn't.

Common attribution windows

The four most common windows you'll set in ad platforms:

• 1-day click — only conversions within 24 hours of a click count. Most conservative.
• 7-day click — current default for Meta and Google for most campaigns.
• 28-day click — old Meta default, now restricted. Useful for high-consideration purchases.
• 1-day view — counts a conversion if the user *saw* (but didn't click) the ad within 24 hours.

Most platforms also support combined windows (e.g., "7-day click + 1-day view").

Why attribution window choice matters

The window you pick determines how much credit your ads get — and bigger numbers in the ad platform don't mean more actual revenue.

• Short windows undercount. A 1-day click window misses customers who click an ad, think about it for two days, and then buy.
• Long windows overcount. A 28-day window credits ads for purchases that would have happened anyway (organic shoppers who happened to also see your ad).
• View-through windows are even noisier. They credit ads the customer saw but didn't engage with — easy to inflate ROAS by 50%+ this way.

The combination of "7-day click + 1-day view" is the current Meta default partly because it produces optimistic numbers that make ad performance look better.

Cross-platform attribution overlap

Here's the part most operators miss: every platform reports conversions using its own window, and those windows overlap. Meta claims a conversion if their ad was clicked within 7 days; Google claims the same conversion if their ad was clicked within 30 days. The same purchase gets reported twice.

In practice, summing reported ROAS across platforms double-counts a meaningful share of revenue. The fix is either:

• Use a third-party MMM (marketing-mix model) or unified attribution layer.
• Trust your ad platforms' numbers individually but reconcile against actual revenue in your store/Stripe.

Omesta does the second. The dashboard shows reported ROAS per platform alongside true revenue and surfaces the overlap.

How to pick the right window

A reasonable default for most e-commerce stores:

• Prospecting campaigns — 7-day click. Short enough to stay close to true performance.
• Retargeting campaigns — 1-day click. The intent signal is strong; longer windows over-credit.
• High-AOV / long consideration cycles — 28-day click + 1-day view, paired with mandatory cross-platform reconciliation.

See iOS 14.5 attribution recovery for what to do when attribution windows fail entirely due to opt-out.

Run a leak scan — see your attribution overlap quantified.