Time-Decay Attribution
Time-decay attribution is a multi-touch model that gives more conversion credit to touchpoints that occur closer in time to the conversion.
In depth
Time-decay attribution applies a decreasing weight to each touchpoint as you move backward from the conversion, typically using a half-life so that an interaction a week before the sale earns more credit than one a month earlier. It works by scoring every touchpoint with a recency-based multiplier and then normalizing those scores so they sum to one conversion. This makes it well suited to longer sales cycles where late-stage nudges, such as a sales call or a retargeting sequence, plausibly do the heaviest lifting toward the close.
The common pitfall is recency bias: time-decay structurally undervalues the awareness touchpoint that first created demand, which can starve the very campaigns that fill the top of the funnel. In a quiz-funnel and lead-qualification workflow, time-decay tends to reward the scorecard quiz and the follow-up emails that arrive shortly before purchase, so use it to optimize closing motions but pair it with first-touch reporting when you need to credit demand creation.
Example in practice
Frequently asked questions
How does the half-life work in time-decay attribution?
The half-life is the period over which a touchpoint's credit halves as it moves further from the conversion. A shorter half-life concentrates credit on the most recent touches, while a longer one spreads it more evenly.
When should I prefer time-decay over linear attribution?
Choose time-decay when later interactions plausibly do more to close the deal, which is common in considered, multi-week purchases. Linear is better when you believe every stage contributes roughly equally.
What is the risk of time-decay attribution?
Its recency bias undervalues the early awareness touchpoints that created the demand in the first place. Relying on it alone can lead you to defund top-of-funnel campaigns that quietly feed the pipeline.