Backlinks continue to be especially valuable for SEO, acting as a signal to search engines that vouches for both the value of your content and the worthiness of your website.

In measuring the success of your backlink efforts and informing your future SEO priorities, the data matters. Depending on the tool you use, your results can vary greatly and — in this case — the more data the better.

With this in mind, we’re excited to share that Moz has the largest link data set, according to a study done by Perficient.

Methodology

The link index study was done by Perficient, a respected publicly-traded consulting firm specializing in digital solutions. This award winning firm regularly publishes insightful studies, focused on SEO trends and topics. For this study, Eric Enge, Principal at Perficient, Search Engine Land author, and well-known SEO SME, led the investigation.

The study compared 3,000 search queries across the Technology, Health, and Finance market sectors to evaluate the link indexes of Moz, Ahrefs, SEMrush, and Majestic. The queries were evenly split across the sectors, and then used to pull results from Google for the top 100 domains. This led to the statistically significant sample size of 85,308 domains. Perficient then used the APIs for all four link indexes and evaluated the results. Perficient also performed manual checks to validate results.

Full disclosure: Moz financed the study, but Perficient conducted it independently — the conclusions are 100% their own, with no influence from Moz.

"The link graph — the sum total of all of the links that connect the pages on the worldwide web — is the foundation of PageRank and the original Google algorithm. While a lot has changed in 20 years, high-authority links are still a driving force in how Google values and surfaces content. Our goal is to reveal as much of the link graph as possible to understand how Google sees the web and rewards authoritative content, while at the same time helping people focus on the highest quality and most actionable links." — Dr. Pete Meyers

Results

The Moz link index reported approximately 90% more links than Majestic, which reported the second-largest. Moz reported the most links per domain 72% of the time.

In link research, size matters. Whether you’re launching a link building campaign, performing competitive analysis, or creating a Google disavow file, finding the most complete set of links to any URL or domain directly impacts the quality of your work as an SEO.

Moz reported the most linking domains 60% of the time.



When performing link research, the number of raw links isn't always as important as the number of unique linking domains. A tool that reports a million links, but all from the same domain, isn't nearly as valuable as a tool that reports 1,000 links from 100 different domains. Links often repeat across the same domain (think footer or sidebar links), so finding the most unique linking domains — as opposed to raw link counts — is often a more useful metric for SEOs.

Moz narrowly trailed Majestic by 0.2% as having the lowest percent of duplicate links.

Link counts can be inflated when tools report duplicate links. For example, some tools might report a link found with both HTTP:// and HTTPS:// as two separate links, even though one canonicals to the other. A lower percentage of duplicate links can indicate better data quality.

This is the second study in recent months to determine that Moz link data stands above the rest. In October of 2020, Search Engine Land compared eight SEO tools, and also noted that Moz reports a significantly higher number of linking domains.

Reviews

Perhaps just as important as the breadth of the data is that Moz tools make managing SEO easier, as these reviews mention:

Carly Schoonhoven, Senior SEO Manager at Obility: “Moz makes my life easier in so many ways. When doing link building, particularly, I absolutely love the link intersect tool. It’s a really great way to find linking opportunities quickly without having to put in a lot of extra effort. I also love that, you know, any data you need is really only just a couple of clicks away, whether it be site errors or backlinks or keywords. It just really is intuitive and makes finding data really fast.”

Kristina Kledzik, SEO Manager at Rover: “Moz has been a critical part of my link building strategies and competitive analysis for five years now, through agency work and in-house SEO. It’s easy to use, easy to understand, and adds an extra layer of information to every website you visit. Definitely a must have for any SEO.”

Lily Ray, SEO Director at Path Interactive: “I love using Moz Link Explorer to see how potential clients are doing compared to their competitors. You can get as granular as looking at the individual URL level, which is really helpful.”