Citation half-life

Citation half-life is the time it takes for the citations a piece of content earns in AI-generated answers to fall to half of an earlier level.

Example

A guide is cited in 40 answers a week across a tracked prompt set at its peak. Some months later it is cited in 20 a week on the same prompts and engines. The time between those two points is the guide's citation half-life for that prompt set.

How it is measured

Citation half-life is not a standardized metric, and teams define it differently. A workable approach is to pick a baseline, such as the peak week or the first full month after publishing, keep the prompt set and engines fixed, and note when the citation count first stays at or below half of the baseline.

Because AI answers vary from run to run, a single low week can be noise. Comparing averages over several weeks gives a more reliable reading than one data point.

Why it matters

Half-life turns citation decay into a rate you can plan around. A short half-life on a topic can suggest the content needs refreshing more often, while a long one suggests the page holds up and other work may deserve the time.

Related terms

• AI citation decay
• Citation share
• Answer variability
• Attribution window
• AI and LLM citation decay: what it is and how to measure it