Attribution

Attribution is how GA4 decides which marketing channels deserve credit when someone converts. Almost nobody buys on the first visit — they find you, leave, come back, and convert later. Attribution is the system that looks at that whole journey and assigns the conversion to one channel, or splits it across several, depending on the rules you've set.

Why it matters

Attribution is the lens you use to decide where your customers actually come from — and therefore where your money and effort should go. Get it wrong and you'll over-invest in whatever channel happens to close sales while starving the channels that started the journey. Two settings drive it: the attribution model (how credit is split) and the lookback window (how far back GA4 looks).

A concrete example

A visitor clicks a paid ad in week one, returns from an email in week three, and converts. With a 30-day lookback window and data-driven attribution, both touchpoints get partial credit. Shorten the window to 7 days and the ad falls outside it entirely — GA4 now credits email alone, and the ad silently looks like it did nothing.

The common misreading

People treat attribution numbers as objective fact when they're the output of settings you chose. If conversions for a channel shift overnight, the channel's performance may not have changed at all — the model or the lookback window did. Before reacting to an attribution number, confirm the rules behind it haven't moved.