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llms.txt GeneratorWhat does a 31-day brand half-life actually mean?
It means brand-level AI presence tends to halve from its peak within about a month. The study’s average brand half-life is 31 days.
The key numbers.
- Brand half-life
- Average time for brand presence to halve from peak.
- 31 days
- Brands analyzed
- Brands covered in the broader longitudinal study.
- 10,991
Visibility gains are real, but they do not stay fixed unless the brand keeps earning fresh support.
The evidence.
| Measure | Result |
|---|---|
| Brand half-life Average time for brand presence to halve from peak. | 31 days |
| Brands analyzed Brands covered in the broader longitudinal study. | 10,991 |
Population and method
Built from 857,138 reports, 108,650 citations, 10,991 brands, and 8 tracked models across a 10-month observation window.
Where the evidence stops
Decay describes observed persistence, not the full causal mechanism behind why a citation disappears.
Brand- and domain-level averages can hide very different retention patterns by query class or model.
Some of the stickiest or most volatile domains come from niche query pockets and should be read as examples, not universal leaders.
What to do with this
- Measure visibility as a moving system, not a one-time citation snapshot.
- Refresh and monitor citation-driving pages on the cadence your models actually decay, not the cadence that feels comfortable.
- Separate durable wins from temporary spikes so the team is not overreacting to short-lived mentions.
This answer matters because it turns a study finding into an operating rule teams can use when they decide what to publish, refresh, or measure next.
Questions about this answer.
Cite this answer.
Source study: Citation Decay“It means brand-level AI presence tends to halve from its peak within about a month. The study’s average brand half-life is 31 days.”
Mack Grenfell · What does a 31-day brand half-life actually mean?
The Half-Life of AI Citations · Trakkr Research · Updated 30 March 2026