Ahrefs' December 2025 observational study
examined 75,000 brands across ChatGPT, AI Mode and AI Overviews. It reported a
roughly 0.737 correlation for YouTube mentions and 0.66–0.71 for branded web
mentions. These are associations with brand visibility, not evidence that
buying mentions causes citations or that an unlinked mention is worth three
backlinks. The study does not establish universal Reddit/Wikipedia/LinkedIn
weights, undisclosed model training composition, or a site's probability of
being recommended. Use the rubric as an explicit planning heuristic and measure
actual answers separately.