Moz’s comparative score estimating a domain’s ability to rank in search results, rather than a score used by Google.
Domain Authority, usually shortened to DA, is a proprietary Moz metric built from its data and prediction model. It is designed to support comparisons between websites. It should not be read as a search engine’s endorsement, an overall business-quality rating or a guarantee that any particular page will rank.
A useful comparison starts with the actual websites competing for relevant queries. A small specialist business does not need to chase the score of a global publishing company to make a worthwhile improvement. Review the pages and links behind the numbers, the audience they serve and whether the search intent matches your offer.
Moz explains that DA can move as its link index and calculations change. Separate changes in a vendor’s estimate from observed changes in your own search traffic, leads or revenue. Buying links simply to raise a third-party score is not a sound success measure.
Takeaway: Use DA as one comparative research signal. Judge the SEO program primarily by relevant visibility, qualified enquiries and business outcomes.
Example
A bookkeeping company compares itself with three firms appearing for the same service queries. One rival has a higher DA but a weak payroll page. The team investigates that page-level opportunity instead of assuming the domain score decides every result.
What to check
Record the vendor, date and comparison set with any DA report. Do not mix DA with another tool’s authority score as if the numbers used an identical model.
For more detail, see Moz: Authority Scoring Guide.