Time-Decay Attribution
AnalyticsAlso: Time Decay Model · Recency-Weighted Attribution
Quick definition
Time-decay attribution is a multi-touch attribution model that gives more credit to the marketing touchpoints closest in time to a conversion. The further back a touchpoint sits in the customer journey, the less credit it receives. It assumes that recent interactions had more influence on the decision to convert.
A customer touches all four, then converts.
Credit distributed
Last-click hands everything to branded search. Upper funnel gets nothing, which is why budgets shift there fast under this model.
How it varies across Australia
Time-decay is more widely used than first-click but still sits behind last-click as the default model for Australian mid-market advertisers. Adoption rises among businesses with longer consideration cycles, where the closing touches are genuinely more influential than early awareness.
See data and tracking patterns across Australian industries →What it actually means
Think about meeting someone at a conference. You hear about them from a colleague six months earlier, you see their content a few times, then you have a proper conversation the week before you sign. Time-decay attribution says that conversation gets the most credit, last week's email gets a little less, the content you saw months ago gets almost nothing. The logic is that influence fades with time.
In practice, the model applies a half-life curve to each touchpoint. A touch that happened the day before conversion might get three or four times the credit of a touch that happened three weeks prior. The exact decay rate varies by platform, but the shape is always the same: a slope that drops off as you move back in time.
Where time-decay earns its place is in longer sales cycles, where a retargeting ad or sales call genuinely is doing the closing work and early awareness touches are less decisive. Where it misleads is in businesses with heavy brand investment, where the awareness built months ago is precisely what made the closing touch possible at all.
Understanding which model fits requires knowing your actual customer journey, not just which model your ad platform defaults to. Most attribution decisions in Australian businesses are made by whoever set up the ad account, not by someone who mapped the journey.
Time-decay is the honest model for businesses where the close really does matter more than the intro. The problem is most businesses use it without asking whether that assumption holds for them.
How it shows up
Time-decay shows up in your ad platform's attribution reports whenever you select it as the active model. In Google Ads, it was available as a rule-based option before data-driven attribution became the default. In GA4, it appears in the Attribution Settings panel and in the Model Comparison tool.
The practical effect: channels used earlier in the journey, such as display, YouTube or top-of-funnel content, receive systematically lower attributed conversions under time-decay than under linear or position-based models. Channels used at the decision stage, such as branded search or direct, receive systematically more. Budget decisions made from time-decay reports tend to accelerate spend toward closing channels and away from awareness channels.
The Australian context
Australian advertisers with shorter average consideration cycles, common in retail and hospitality, sometimes find time-decay produces attribution that looks intuitive but actually understates the role of paid social and content in the upper funnel. The challenge is that Australia's smaller media market means upper-funnel channels are already fighting for budget justification. A model that structurally under-credits them makes that fight harder.
Where people get this wrong
Related terms
Common questions
When should I use time-decay attribution?
Time-decay fits best when your sales cycle is two to six weeks and the final one or two touches are genuinely doing the decision-making work. It is a poor fit when your business relies on brand or awareness advertising, because those early touches will be systematically under-credited and eventually defunded.
How is time-decay different from last-click?
Last-click assigns all credit to a single final touch. Time-decay distributes credit across every touch but weights recent ones more heavily. Time-decay is more generous to the middle of the funnel, but early touches still receive very little credit compared to linear or position-based models.
Does Google still use time-decay attribution?
Google Ads removed time-decay as an option in 2023, with data-driven attribution now the default. It remains available in GA4 as a model comparison option. If your reporting was built on time-decay before the change, your attributed conversion numbers shifted when the default changed.
How do I know which attribution model is right for my business?
Run an attribution model comparison in GA4 and look at which channels gain or lose credit between models. Then match those shifts against what you actually know about your customer journey. Pair this with incrementality testing to check whether the channels gaining credit under any given model are producing real lift.
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About New Rebellion
New Rebellion is a marketing intelligence consultancy. We build tools, score Australian businesses on how their marketing actually performs, and publish Debrief every day. This dictionary is part of how we work in the open.
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