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Research and Studies

Do Links Still Matter for SEO in 2017?

Blue Chains In Cyberspace On Black

In today’s post, I’ll show you data from three different dates over the past year that illustrate why links remain a powerful ranking factor. I’ll also discuss in detail why Google still uses them, and why they are likely to remain a powerful ranking factor for some time to come.
In July of 2016, we published our first study on Links as a Ranking Factor. Today’s post updates that data with a fresh analysis of links as a ranking factor, to see if there is any indication of a decline in their importance. In fact, we have analyzed the power of links as a ranking factor on three different dates, as follows:

  1. May 2016
  2. August 2016
  3. May 2017

The Results

Let’s dig right in and look at the results across all three data sets that we pulled:
Bar Chart Shows Quadratic Mean Spearman Correlation Score
Note that the same 6,000 queries were used in all three data sets, and we see that the value stays steady and strong throughout the time period. Some movement back and forth is natural. We used 6,000 queries because that is what we did with the original study on this topic. With the Study Two and Study Three data sets, we also pulled data samples for 16,000 queries. Here are the correlation scores for those two data sets of 16K queries:
Bar chart shows Quadratic Mean Spearman Correlation Score
Once again, both data sets show strong results. Note: See the methodology section below for an explanation of what a “Quadratic Mean Spearman Correlation Score” value actually means.
In the first study, we also took a view in which we aggregated the normalized link counts (see the methodology section below for an explanation of what that is) by ranking position. The purpose of this approach was to help adjust for the fact that the relevancy and quality of the content are such significant ranking factors, and to help us further evaluate how links might matter. Here is what we saw:Bar Chart Shows Aggregate Link Correlation by Ranking Position
In this data, there is some apparent erosion, but the story is quite different if you look at the results for the two 16K query sets:

For this data set, we see a lift between Study Two and Study Three, which is in contrast to the 6K data set. As a result, my belief is that this is simply normal movement of the rankings from a variety of factors.

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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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