Domain authority

Domain Authority is a score, originally from Moz, that predicts how well a domain might rank, on a 0 to 100 logarithmic scale derived largely from the backlink profile. Ahrefs has an analog called Domain Rating, and other tools have their own versions. These scores are useful for comparing sites and tracking relative progress, and they are widely cited in the industry.

The critical clarification is that domain authority is not a Google ranking factor. Google has stated repeatedly that it does not have a single site-wide authority score that works the way these third-party metrics do. The metrics are estimates built by SEO vendors to approximate ranking potential; Google's own systems use many signals, and while the API leak suggested site-level signals exist, they are not the same as a vendor's DA number.

So the right use of domain authority is as a relative, directional gauge: is my link profile getting stronger, how do I compare to the competitors ranking for my targets, is a prospective link from a stronger or weaker site. The wrong use is treating it as the thing Google measures, or optimizing for the score itself. We use authority metrics comparatively, to gauge competitive difficulty, not as a stand-in for what Google actually ranks on.