A Data Driven Guide To Anchor Text (And Its Impact On SEO)

David McSweeney
David is the owner of Top5SEO and a white hat SEO evangelist. SEO case studies make him a lot happier than they should, and he has a tendency to overuse ellipses...

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  • Referring domains 282
  • Organic traffic 585
Data from Content Explorer tool.

    There’s a lot of information out there about anchor text.

    But depending on which guide you read, you might think that you should:

    a) Build lots of anchor text rich links to shoot your site to the top of Google!
    b) Avoid building any anchor text links or you’ll be banned forever from search and put on an FBI watch list!

    So which is true?

    Well, like many things in SEO, the truth lies somewhere in between. So today we’re going to deep dive into the topic and, as usual, rely on data (rather than opinion) to form our conclusions.

    Let’s start by defining exactly what anchor text is and how it influences search rankings.

    Anchor text refers to the visible, clickable words used to link one web page to another.

    anchor-text

    Example: In this sentence, the blue words are the anchor text.

    Let’s say Ahrefs published an article that we wanted to rank for the keyword “marketing toolset”. Here are some of the ways that other websites might choose to link to us:

    Exact Match — the anchor text is the exact keyword phrase we are looking to rank our article for:

    Ahrefs is a data-driven marketing toolset powered by a huge index of backlinks, keywords and content.

    Partial Match/Phrase Match - the anchor text contains the keyword phrase we are looking to rank for:

    Ahrefs is a data-driven marketing toolset powered by a huge index of backlinks, keywords and content.

    Branded — the anchor text is the name of our brand:

    Ahrefs is a data-driven marketing toolset powered by a huge index of backlinks, keywords and content.

    Naked URLs — the anchor text is a ‘naked’ URL (i.e. as it would appear in a browser):

    Ahrefs (https://ahrefs.com) is a data-driven marketing toolset powered by a huge index of backlinks, keywords and content.

    Generic — the anchor text is an unspecific, generic phrase which does not include our target keyword (i.e. ‘click here’, ‘this site’, ‘this article’)

    Ahrefs is a data-driven marketing toolset powered by a huge index of backlinks, keywords and content. Click here to go to their site.

    LSI Keywords — the anchor text is a synonym for, or closely related to our target keyword.

    Ahrefs is a data-driven promotional toolset powered by a huge index of backlinks, keywords and content.

    Other types of anchors include:

    • Author — your name would be the anchor.
    • Title Tag — your page title is the anchor. Often these will also be partial match.
    • Image links — the alt text may be counted as the anchor.

    By running the “Anchors” report in Ahrefs’ Site Explorer, we can see that several of the anchor text types listed above have been used to link to our SEO tips article.

    Site Explorer > Enter URL > Explore > Backlink profile > Referring domains > Anchors

    anchors-report

    Now let’s take a look at how that choice of anchor text may influence our rankings.

    Search engines (from here on I will refer to Google) use the anchor texts linking to a page as an indicator of the page’s topic; i.e which keywords it should rank for.

    In simple terms, if I was to link to a page from this article with the anchor text “dog biscuits”, this would indicate to Google that I (or Ahrefs) believe that the linked site is a good fit for that query.

    And again, to simplify:

    The more sites that link with the anchor containing the phrase “dog biscuits” (exact or partial), the more certain Google will be that the linked page should rank for that query.

    But of course, nothing in SEO is ever simple. At least not any more.

    Early Google’s (Over) Reliance On Anchor Text

    Anchor text was weighted heavily in Google’s original algorithm.

    In their 2008 paper “The Anatomy of a Large-Scale Hypertextual Web Search Engine”, Google founders Sergey Brin and Larry Page explained:

    The text of links is treated in a special way in our search engine. Most search engines associate the text of a link with the page that the link is on. In addition, we associate it with the page the link points to. This has several advantages. First, anchors often provide more accurate descriptions of web pages than the pages themselves.

    (yes, they were much more transparent back then)

    Using anchor text would also allow Google to determine the topic of (and return in search results) media formats where on-page signals could not be used.

    Second, anchors may exist for documents which cannot be indexed by a text-based search engine, such as images, programs, and databases. This makes it possible to return web pages which have not actually been crawled.

    The logic was sound, and the early results impressive, however…

    This was VERY open to manipulation.

    To rank a web page for a query, all an SEO had to do was point multiple links at it with their target keyword as the anchor.

    More keyword rich anchor text links than your competitor = you won that particular rankings battle.

    This also lead to some amusing examples of ‘Google Bombing’ — where SEOs would show how easy it was to game Google by pointing anchor text links at non relevant pages and ranking them for the lulz.

    This 'Google Bomb' successfully ranked George Bush for "miserable failure" for over 3 years

    One ‘Google Bomb’ successfully ranked George Bush for the term “miserable failure” for over 3 years

    Clearly things had to change.

    Google Fights Back Against Manipulative Anchor Text

    Since us SEOs can’t have nice things without spamming them to death, Google gradually began to reduce the weighting of anchor text in their algorithm.

    But it wasn’t until 2012 that the Google Empire really struck back.

    empire-strikes-back

    In April of that year the first iteration of Google Penguin rolled out and hammered low quality and manipulative link building.

    penguin

    Anchor text was one of Penguin’s primary targets, and many websites that had been overly aggressive with their exact match anchor text links saw their rankings tank overnight.

    It may have only impacted 3% of search queries, but as usual, Google’s ‘Project Fear’ had done the trick.

    This email, received by Ryan Stewart of Webris from a client he built some solid white hat links for, sums up today’s twitchiness about anchor text.

    We are looking to dilute our anchor text profile. We hired you to build white hat links – anchor texts should ONLY contain our brand name! Anything else is manipulation and we will get penalized by Google.

    So is Ryan’s client correct? Should we really be avoiding using ANY keyword phrases in our anchor text to avoid penalty? And for that matter, does anchor text continue to influence rankings?

    To find out, we conducted 2 studies:

    The first study was small and looked at anchor text influence on rankings in competitive niches. The second study cast the net rather wider and looked at anchor text influence across 16,000 keywords.

    I manually analysed the rankings of 51 keywords in big, high paying niches – think pay day loans, law, finance, insurance, health etc – with high keyword difficulty scores.

    Here is what I discovered.

    Influence Of Exact Match Anchors

    First I took a look at the percentage of exact match anchors from individual referring domains — calculated against the total number of individual referring domains to the URL.

    I included the median figure as there were certain niches (for example payday loans) that were very anchor text heavy, so I was conscious they may distort the percentages.

    exact-match

    Now for the actual volumes (number) of exact match anchor links.

    volume

     

    INFERENCES

    The data above would suggest that exact match anchors still have some influence on top placements in competitive niches.

    Average is high, but as mentioned the data is skewed somewhat by certain niches, so I would err towards the median results and suggest a percentage of 1 to 2% (and a low number, i.e. 2 or 3) would be safe and potentially help with rankings at page level.

    Influence Of Phrase Match Anchors

    Here are the average and median percentages of phrase match anchors by position.

    This is where the search phrase appeared in its entirety within the anchor text(including exact match) and again is calculated as a percentage of the total number of referring domains to the URL.

    phrase-match

    And the volumes…

    phrase-volume

    INFERENCES

    The data above would suggest that anchor text containing a target phrase continues to influence rankings.

    Average and median figures are closer than with exact match, and it would appear that around 30% of anchors containing a target phrase would be a desirable and safe level.

    It would also appear that a fairly even split between DoFollow and NoFollow correlates with rankings.

    Number Of Domains With At Least 1 Keyword Anchor Link (Phrase Or Exact)

    The following data shows the number of ranking domains containing at least one anchor text link (split by phrase and exact).

    one-anchor-link

    If we look at SERP position 1, it becomes clear that there is a correlation with a page’s link profile containing at least one keyword rich anchor and its ability to rank highly for that keyword.

    no-keyword

    After completing my initial study, we wanted to tap into Ahrefs HUGE data and scale things up to see if the takeaways would remain the same.

    This time we looked at the top 20 results across 16,000 keywords — meaning we analysed a whopping 320,000 pages in total!

    For each page (URL + Keyword) we collected the following metrics:

    • Ahrefs rank of the target URL
    • Total # of referring domains of the target URL
    • # of partial keyword match referring domains
    • # of exact keyword match referring domains
    • # of DoFollow partial keyword match referring domains
    • # of NoFollow partial keyword match referring domains
    • # of DoFollow exact keyword match referring domains
    • # of NoFollow exact keyword match referring domains
    • Avg. DR of the partial keyword match referring domains
    • Avg. DR of the exact keyword match referring domains

    Experiment #1

    First off, we wanted to find out if there was a correlation between the percentage of exact/partial match anchor text links in a page’s backlink profile and its ability to rank higher in search.

    Here’s what we got:

    anchor-text1

    INFERENCES

    It certainly appears that higher ranking pages tend to have a larger percentage of exact match anchor text links in their backlink profile.

    Although, perhaps surprisingly, the correlation of partial match anchor text links wasn’t too prominent.

    But that was a percentage of links from the total backlink profile of a page.

    What if we look at a raw number of referring domains with both exact and partial match anchor text links?

    anchor-text2

    The takeaway here is clear – anchor text links from a variety of different domains correlate with higher rankings in Google.

    Experiment #2

    One thing that Experiment #1 revealed is that pages with more backlinks from different domains tend to outperform pages with less backlinks.  This is what we would expect to see.

    So in Experiment #2 we decided to level the effect of a strong backlink profile and only compare the data on pages with similar numbers and quality of incoming links.

    We limited our keywords to those where the Top 5 Google results’ URL Rank had standard deviation of less than 30% of their average value. This left us with about 2,000 keywords (out of the original 16,000).

    Here’s how this changed the numbers:

    anchor-text3

    INFERENCES

    In cases where pages had equally strong backlink profiles it was the % of partial match anchor text links that mattered the most, while the % of exact match links stayed more or less consistent across the Top 5 results.

    Both case studies clearly demonstrated that keyword usage in anchor text continues to influence search rankings.

    However…

    The Caveats

    Firstly, there is the standard correlation does not imply causation.

    Google has over 200 ranking factors, and while the data above would suggest that keyword usage in anchor text continues to be one of them (and you probably should build some keyword rich links) there are numerous other factors which may have influenced the rankings of these pages.

    Secondly, we are unable to tell if any of the links I/we discovered have subsequently been disavowed, which could be the case in some of the particularly keyword rich profiles.

    So as always, take everything with a grain of salt and conduct your own tests.

    That being said…

    I Believe Anchor Text Continues To Influence Rankings

    Caveats in place, I’m going to stick my neck out and say that keyword prevalence in anchor text is almost certainly still a ranking factor, and perhaps a bigger one than Google would like us to believe. It’s what the data tells us.

    You can quote me on that.

    So, if you’re building links (or someone is building links for you) then you probably don’t need to be too sensitive about anchor text, and a few keyword rich links as part of a diverse profile should help you rank.

    Just don’t go crazy though and from the data above, I would suggest exact match at around 2% and phrase match at around 30% will keep you on the right side of Google.

    Of course, as always, the strongest and safest links are those which are editorially earned and you should always avoid building low quality links, regardless of anchor text.

    Over To You…

    What’s your thoughts on keyword rich anchors?

    Do you continue to build them, or do you avoid them like the plague? Any observations from your own site? Have you been penalised in the past? Any other questions?

    As always it would be great to hear from you, so please drop a comment below!

    David McSweeney
    David is the owner of Top5SEO and a white hat SEO evangelist. SEO case studies make him a lot happier than they should, and he has a tendency to overuse ellipses...

    Article stats

    • Referring domains 282
    • Organic traffic 585
    Data from Content Explorer tool.

    Shows how many different websites are linking to this piece of content. As a general rule, the more websites link to you, the higher you rank in Google.

    Shows estimated monthly search traffic to this article according to Ahrefs data. The actual search traffic (as reported in Google Analytics) is usually 3-5 times bigger.

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