Domain Authority

Domain Authority (DA) is a proprietary metric originally developed by Moz that estimates how competitively a website can rank in search results, scored on a logarithmic 1–100 scale. It is calculated from link-profile features: how many unique referring domains link in, how strong those linking domains are, link velocity over time, and topical relevance. Critically, DA is a third-party predictive score — Google does not use it and explicitly disclaims it as a ranking factor.

Equivalent metrics from other vendors include Ahrefs Domain Rating (DR), SEMrush Authority Score (AS), Majestic Trust Flow / Citation Flow, and LinkResearchTools DPR. Each uses a different proprietary algorithm over its own link index, so the scores aren't directly comparable across tools — a DA of 50 doesn't equal a DR of 50. They're useful as relative comparisons within a single tool, not as absolute benchmarks.

The logarithmic scale matters: moving from DA 20 to 30 is much easier than DA 50 to 60. A new site can typically reach DA 20-30 within 12 months with modest link acquisition; reaching 50+ takes years of consistent authority building. This non-linearity is why "we need to hit DA X by Y" goals tend to fail in the second half — they're fighting compounding difficulty.

Common misuses: treating DA as a direct ranking factor ("we lost rank because our DA dropped 2 points" — DA drops can be measurement noise, not real signal); chasing high-DA backlinks without context ("get me a DA 80 link" — a topically irrelevant link from a DA 80 site is often worth less than a relevant DA 30 link); and conflating DA with content quality. Google ranks pages, not domains; DA is a domain-level proxy that doesn't capture page-level signals.

Practical use: DA / DR / AS work well for competitive benchmarking ("our top 5 competitors have DR 45–60, we're at 28") and for filtering link-prospecting lists ("only pitch sites with DR > 20 in our vertical"). They work poorly as KPIs to optimize directly — moving DA without underlying behavior change is gaming a proxy, not improving the underlying business.