How view-through tracking works
When an ad is served on a Meta, Google Display, or TikTok placement, the ad platform records an "impression" event with the user's browser ID. If that same user later visits the advertiser's site and triggers a conversion event (via pixel or server-side), the platform checks: did this user see this advertiser's ad recently?
If yes — within the platform's view-through attribution window — the platform attributes the conversion to that earlier impression. The user never clicked. They might have ignored the ad entirely. The platform doesn't know; it only knows the impression happened and the conversion happened, and they were the same user within the window.
Typical default windows:
- Meta: 1 day view, 7 day click (configurable)
- Google Display: 1 day view, 30 day click (configurable)
- TikTok: 1 day view, 7 day click (configurable)
- YouTube: 1 day view for some skippable ads, more for engaged views
Search ads (Google Search, Microsoft Search) don't support VTC because the user has to click a search ad — there's no "passive view" equivalent of seeing a search result.
Why VTC is famously over-inflated
The structural problem: ad platforms attribute view-through credit based on co-occurrence, not causation. A user who saw your ad on a sports site at 9am, never noticed it, and then converted at 3pm because they got an email from your sales team — that VTC is credited to the morning ad impression. The platform doesn't know about the email.
Common scenarios that produce false-positive VTCs:
- User had the ad load below the fold and never scrolled to it
- User was already a customer or already in your retargeting audience because of prior intent
- User would have converted anyway — they came to your site from a Google search for your brand name
- Ad-blocker users still trigger view events on some platforms before the ad is hidden
- The "viewability" definition is loose — for Meta, a viewable impression requires only 1 pixel of the ad in the viewport for 1ms (for display) or 50% in the viewport for 2 seconds (for video)
Independent studies have estimated that 30-60% of view-through conversions would have happened anyway, meaning the ad had no causal role. The exact number varies by platform, vertical, and audience, but the direction is consistent: VTC overcounts.
How to think about VTC in reporting
Three practical rules used by experienced media buyers:
- Report click-through and view-through separately. Never sum them as if they're the same. The default ad-platform dashboards often combine them; switch the view to show click-through only as your primary metric.
- Heavily discount VTC numbers when evaluating campaign performance. A common heuristic: divide VTC by 2 or 3 before comparing to click-through. This crudely accounts for the false-positive rate.
- Use VTC for upper-funnel display campaigns intentionally. If you're running display specifically for awareness and you don't expect clicks, then VTC is the metric you have to use. Just be honest about its limitations when reporting.
What this means for affiliates
For pure affiliate marketing, VTC mostly doesn't apply directly. Affiliate networks pay on click-through conversions only — the user has to click your affiliate link before the conversion happens for you to get the commission. VTC is an ad-platform concept used by the advertiser (the merchant), not by the affiliate.
Where VTC matters for affiliates:
- If you run paid display ads (Google Display, Meta retargeting) driving to a bridge page with affiliate links, the ad platform may report VTC alongside click-through conversions. Treat VTC as noise relative to your real economic data — which is the click-through conversions that actually pay commission.
- If you're a hybrid affiliate (running ads to your own offer and earning commission on referred sales), VTC reporting from your ad platform will overstate effective ROAS. Discount accordingly.
- For affiliate networks themselves, look for platforms that report "cookie attribution" or "VTC" if you're trying to recover credit for sales where your cookie was overwritten. Most don't.
For the broader context on how view-through and click-through fit into an end-to-end tracking stack, see the tracking-setup playbook.