Time-Decay Attribution

Time-decay attribution gives more credit to touchpoints that happened closer to the conversion and less to ones further back. Credit fades with age, usually on a seven-day half-life — a touchpoint a week before converting earns roughly half the credit of one the day before. The closing channels win; the early discovery channels get only a sliver.

Why it matters

Time-decay encodes the belief that recent interactions weighed more heavily on the decision than distant ones. For short, momentum-driven sales cycles that's often right — what someone saw yesterday matters more than a click from three weeks ago. It's a softer version of last-click: it still favours the finish, but it doesn't erase everything that came before.

A concrete example

A path runs organic search 14 days out, email 5 days out, and direct on the day of conversion. Under time-decay in GA4, direct earns the lion's share, email a moderate amount, and the two-week-old organic search visit barely registers. The same conversion under first-click would have handed organic search everything.

The common misreading

Time-decay systematically underrates the channels that start long journeys, and it's easy to read its low early-touch numbers as proof those channels don't matter. For a considered purchase that takes weeks, the discovery channel may be the most important one — and time-decay will hide it. Match the model to your sales cycle before trusting its verdict.