PageRank vs Domain Authority: Which Metric Should You Trust?

With multiple domain authority metrics available, SEO professionals often wonder which one to trust. This article compares Open PageRank, Moz's Domain Authority, Ahrefs' Domain Rating, and other popular metrics to help you make informed decisions.

The Origins: Google PageRank

To understand modern domain authority metrics, we need to start with the original PageRank algorithm developed by Larry Page and Sergey Brin at Stanford University in 1996. PageRank was revolutionary because it treated links as votes of confidence. A link from an important page passed more value than a link from an obscure one.

Google used PageRank as a key component of its search algorithm and, until 2016, publicly displayed PageRank scores in its toolbar. When Google stopped sharing these scores, third-party tools stepped in to fill the void with their own metrics.

Open PageRank: The Transparent Alternative

Open PageRank is an open-source implementation of the original PageRank algorithm. It uses data from Common Crawl, a non-profit that maintains one of the largest publicly available web archives, containing billions of web pages.

Strengths of Open PageRank:

• Transparency: The methodology is public and based on well-understood algorithms
• Free access: The data is freely available without subscription fees
• Historical relevance: Closely mirrors the original Google PageRank methodology
• Large dataset: Covers over 10 million domains

Limitations:

• Updated periodically rather than in real-time
• Limited additional metrics beyond the core score

Moz Domain Authority (DA)

Moz's Domain Authority is perhaps the most widely recognized third-party authority metric. DA predicts how well a website will rank on search engines using a scale of 1 to 100.

Strengths:

• Industry standard, widely referenced and understood
• Regular updates and methodology improvements
• Integrates with a comprehensive suite of SEO tools

Limitations:

• Proprietary methodology not fully disclosed
• Requires paid subscription for full access
• Has undergone major methodology changes that affected historical comparisons

Ahrefs Domain Rating (DR)

Ahrefs' Domain Rating measures the strength of a website's backlink profile on a logarithmic scale from 0 to 100. It focuses specifically on the quantity and quality of referring domains.

Strengths:

• Massive link database with frequent updates
• Clear focus on backlink strength
• Detailed breakdown of contributing factors

Limitations:

• Expensive subscription required
• Different methodology makes direct comparison with other metrics difficult

Key Differences Between Metrics

Scale and Interpretation

Open PageRank uses a 0-10 scale like the original Google PageRank, while Moz DA and Ahrefs DR use 0-100 scales. This difference affects how you interpret scores. A PageRank of 5 is quite respectable, while a DA of 5 would be very low.

Data Sources

Each tool crawls the web independently, meaning they may have different coverage. Open PageRank uses Common Crawl data, while Moz and Ahrefs maintain their own proprietary web crawlers. This can lead to discrepancies, especially for newer or less popular websites.

Methodology Transparency

Open PageRank's biggest advantage is its transparency. The algorithm is well-documented and based on established computer science research. Proprietary metrics from Moz and Ahrefs keep their exact calculations secret, making it harder to understand why scores change.

Which Metric Should You Use?

The best approach is to use multiple metrics as complementary data points rather than relying on any single score. Here are some guidelines:

• For quick checks and free analysis: Open PageRank provides reliable data without subscription costs
• For client reporting: Moz DA is widely recognized and easily understood by non-technical stakeholders
• For detailed backlink analysis: Ahrefs offers comprehensive link data alongside DR
• For competitor benchmarking: Use the same metric consistently to track relative changes over time

What Really Matters

Remember that all these metrics are proxies attempting to measure something Google doesn't share publicly. None of them are actual Google ranking factors. The most important things remain:

• Creating valuable content that attracts natural links
• Building genuine relationships in your industry
• Providing excellent user experience
• Maintaining technical SEO best practices

Use domain authority metrics as diagnostic tools and progress indicators, but don't obsess over specific scores. Focus on the underlying activities that improve authority, and the metrics will follow.