Original research with confidence intervals, methodology links, and downloadable data.
SISTRIX measured 82,619 ChatGPT prompts over 17 weeks and found that 74% of cited domains rotate out within seven days. A single probe tells you what ChatGPT cited on that day — not what it will cite tomorrow.
When ChatGPT and Perplexity are asked the same query, only 11% of cited domains overlap. This means any 'AI visibility score' that averages across engines is statistically meaningless — you cannot average across distributions with 89% divergence.
Perplexity's citation probability drops sharply with content age. Pages updated in the last 30 days have a 45 percentage-point advantage over pages older than 18 months. Content older than 18 months drops entirely from Perplexity's citation set.