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Research and Studies

Links as a Ranking Factor in 2019- Still Going Strong

Link Ranking Factor

In today’s post, I’ll share the results from the fourth of our “Links as a Ranking Factor” studies. We conducted the first of these studies in May 2016 and have been tracking the same query set over time to measure any material shifts in the role of links. In this year’s study, we also looked at different market sectors to see how the role of links may vary by market sector.

We have also increased the number of queries we’re examining over time. We did that to make sure that we had enough data for the market sector analyses to be meaningful. The breakout of the month for each of our studies, and the number of queries examined per study, is as follows:

  1. May 2016 – 6K queries
  2. August 2016 – 16K queries
  3. May 2017 – 16K queries
  4. August 2018 – 27K queries

Each of the query data sets includes the original query sets from the earlier studies, so I’ll show an apples-to-apples comparison of those results, as well as the larger-scale results from this year’s study. As a bonus, I’ll also comment on the increase in scope and quality of Moz’ Link Explorer

The Results

As with our prior studies, we received the gracious support of Moz by allowing us to access Link Explorer to pull the data for our study. Link Explorer went into Beta in March 2018 and represents an ambitious effort by Moz to expand the size of their index. In short, it looks like they succeeded:

Growth Of Moz Index

For the link study itself, the first set of charts that we will look at are based on the total number of links pointing to the ranking page. For these, we calculated the Quadratic Mean Correlation score. Jump down to the methodology section to see what a “Quadratic Mean Spearman Correlation Score” value actually means. Here is a look at that data for 6K queries across all four instances of the study that we’ve run to date:

Quadratic Mean Spearman Correlation For Links As A Ranking Factor 6k Queries

Note that the same 6,000 queries for this chart were used in all four data sets. While this looks like it shows some level of decline, the reality is that this movement is within normal statistical variance. For all intents and purposes, this already shows a strong correlation between total links to its page and its ranking.

Beginning with the second study, we upped the query count to 16,000 queries. We carried that same set of 16K queries through to this year’s edition of the study. Here are the correlation scores for those three datasets of 16K queries:

Quadratic Mean Spearman Correlation For Links As A Ranking Factor 16k Queries

Once again, all three sets show strong results, and the variance is within normal ranges of statistical variance.

In this latest version of the study, we updated the query count to 27K queries. This comes in at a solid value as well:

Quadratic Mean Correlation For Links As A Ranking Factor 27 QueriesOne of the more notable findings is that for the first time in all the studies that we’ve done, we see that the Moz DA and the Moz PA are better predictors of ranging than the total link count! The data for this is as follows:

Moz Da And Moz Pa Vs. Total Links (august 18)

As with prior studies, we compared the total link correlation for commercial and informational queries:

All Vs. Commercial Vs. Informational Queries (august 18)

Next up, in this year’s study, we evaluated how links might vary as a ranking factor across market segments. In this first view, let’s look at that for commercial queries, divided into Medical, Financial, Technology, and Other segments:

Commercial Queries Sector Analysis Lowres

This data shows that links are a much bigger ranking factor for financial queries then for other types of queries. Before we draw a final conclusion for that though, let’s also look at a sector analysis for informational queries:

Informational Queries Sector Analysis

Starting with the first study, we also aggregated the normalized link counts (see the methodology section below for an explanation of what that is) by ranking position.

The reason this view is important is that relevancy and quality are very large ranking factors, as they should be. In addition, there are many other factors such as Google’s need to show diversity in the SERPs (see the section titled “Why Aren’t the Non-Aggregated Correlation Values Higher?” for more detail on this). In the aggregated link analysis, we get a summarized view of the impact of links spread across a large array of search results. Here is what we saw looking at the 6K query set across all four studies:

Aggregate Link Correlation By Ranking Position May 16, Aug. 16, May 17, Aug. 18

Here is the data for the 16K query set across the last three studies:

Aggregate Link Correlation By Ranking Position Aug.16, May 17, Aug. 18Here is the data for the 27K query set for this latest study:

Aggregate Link Correlation By Ranking Position Aug. 18

In summary, our aggregated view shows a very powerful correlation between links and ranking position.

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Eric Enge

Eric Enge is part of the Digital Marketing practice at Perficient. He designs studies and produces industry-related research to help prove, debunk, or evolve assumptions about digital marketing practices and their value. Eric is a writer, blogger, researcher, teacher, and keynote speaker and panelist at major industry conferences. Partnering with several other experts, Eric served as the lead author of The Art of SEO.

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