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Research and Studies

Direct Measurement of Google Plus Impact on Search Rankings

Many of you know that I have been working for a long time on a study to attempt to directly measure the impact of Google+ Shares on Google’s search rankings. This study has attempted to measure “causation”, not “correlation” – i.e. to see if we could prove some impact on rankings from Google+ shares. This article presents the results of that work.
This edition of the study was launched at SMX Advanced where I presented results I had from an earlier study we had done that convinced me that links in shares from Google Plus and Facebook behave like traditional web-based links. This was later disputed by Matt Cutts in his keynote interview by Danny Sullivan, leading to a live discussion with me on stage
The brief discussion we had led to my agreeing that I would rerun the study that we had done with some guidance from Matt on potential problems. While this input was limited in nature, it did lead to some ideas on how to improve the testing.
The goal of this effort was to measure the impact that Google Plus Shares have on discovery, indexing, and ranking of content, for results that are not personalized. The results of this new study are presented in this post.
And here is the shocking result in a nutshell. In our study, and in my opinion, Google Plus Shares did not drive any material rankings changes (of non-personalized results) that we could detect. To be fair, our study had some limitations – read on so you can judge for yourself if this test changes the way you think about Google Plus and SEO!

Let the Debate Begin

Basic Study Structure

We picked 3 different sites to use in this test, all of which have been on the web for at least 2 years or more. The 3 sites were:

  1. BuyVia
  2. Perficient Digital
  3. Travel New England

We then wrote 2 different relevant articles for each site. One of these was used as a “Test Page”, and the other was used as a “Baseline Page”. Both pages were implemented without any links to them from any source whatsoever. Both of them received an initial set of Google+ Shares, 6 for the Test Pages, and 40 or more for the Baseline Pages.
From there, the paths diverged. We provided the Baseline Page no further attention other than to monitor indexing and ranking behavior. For the Test Page, we sent additional shares in two waves:

  1. At least 25 shares on August 4th, 2013
  2. 4 more shares from very authoritative profiles between August 28th and September 1st.

Throughout the entire process, we monitored ranking behavior for the pages on a number of different long tail search terms. The August 4th and late-August burst of shares is particularly important, because if Google+ Shares are in fact a direct ranking factor, there should be noticeable changes in rankings for the Test Pages after those shares occur. This is the basic premise the study was designed to test.

What Makes Our Study Different

Plain and simple, this is not a correlation study. For the record, I believe that correlation studies are extremely valuable, but as we know, correlation is not causation, and our study attempts to directly measure if Google Plus shares cause changes in ranking.
To accomplish this we restructured the study in several ways from the one that I presented at SMX Advanced. To start, we set the following goals:

  • Eliminate accesses to the page by humans or 3rd party tools prior to discovery of the pages by Google.
  • Minimize the risk of the test pages receiving links throughout the entire study.
  • Check at every major step to see if there were any links implemented to the site.
  • Pick a panel of handpicked participants to work with us on the study. The reason we did this was so we could have better control over their behavior.

Detailed Methodology

Here is a more detailed look at the methodology:

    1. As noted above, we handpicked 3 sites for this phase of the study.
    2. We published 2 different articles (the Test Page and the Baseline Page) on each of the 3 different sites and implemented zero links to them. In addition, the pages were uploaded to the site by direct FTP upload to ensure that the site’s own publishing environment did not introduce any variables.
    3. The articles we had written for the study contained content which was highly relevant to the site on which it was placed.
    4. No Google programs were referenced in these pages including Google Analytics, Google Plus buttons, or anything else. The only links out from these pages is to other pages on the site on which they resided.
    5. We revealed the existence of the Test Pages and the Baseline Pages to no one. Until people were asked to share them, I (Eric Enge) was the only human being that knew the URLs for the pages.
    6. We hand-picked people to implement Google Plus shares to the pages in the study.
    7. All shares were done via the use of a Study Control Page. This page was used to keep participants from visiting the pages themselves, and I explain why we did that and how this works in more detail below.
    8. We sent Google Plus Shares to the Test Pages in 3 waves, as follows:
      • An initial wave on 7/19/2013 of 6 shares
      • A second wave on August 4th of 25 or more shares
      • A final wave of 4 authoritative Google Plus profiles shared the content between 8/28/13 and 9/1/13
    9. We sent Google Plus Shares to the Baseline Pages in 1 wave, with all the shares taking place on 7/19/13.
    10. We worked hard to minimize or eliminate any visits to the pages, including asking the study participants to not visit them unless they agreed to use a Safari browser with no SEO plugins.
    11. At each stage, each share was accompanied by a strong disclaimer very similar to the following:

Social Study Disclaimer

  1. All pages were monitored to verify that no links were implemented to the pages. Tools used to monitor links were Webmaster Tools, Majestic SEO, Open Site Explorer, and Ahrefs. As a final check, we also checked incoming referrers in Google Analytics.
  2. Results were tracked daily over the course of the study.

In short, the study methodology was designed to maximize the chances that the Google Plus Shares were the only possible factor that could result in content discovery, indexing, and/or rankings changes for the Test Pages.
The authoritative profile shares concept was suggested to me by Mark Traphagen of Virante, Inc, who has also provided advice and counsel during other stages of this study.

How the Study Control Page Works

As mentioned above, people executed their Google Plus shares using a Study Control Page. The reason for this is that browser plugins could introduce variables into the test. For example, a browser may have a plugin installed that queries the Google Plus API resulting in Google learning about the page that way. This was particularly important during the part of the test where we were examining discovery behavior. The study control page used looks like this:
Social Study Control Page
Participants were instructed to click the +1 button, and then to enter in the provided description. The presence of the description turned the +1 into a Google Plus Share.

Google Plus Shares Pass PageRank

The reason why many people believe that these shares can drive ranking is that the code for the link on the Google Plus pages does not include a NoFollow attribute. Here is an example of the code for one of the shares:
Google Plus Shares Pass PageRank
As you can see in the code above, the link is implemented in two pieces. The first is the image link, which does have the NoFollow attribute, and the second is the text link, which does not have the NoFollow attribute. This means that it passes PageRank!
Please note that Joshua Berg of RealSMO did a lot of great work and research in this area, and freely shared that with me for this study.

Possible Sources of Error

There are three main possible sources of error:

  1. Missing Links: It is possible that links were implemented to the pages that did not show up in our monitoring tools. This is not an insignificant potential problem, as by my estimate the cumulative links found by Open Site Explorer, Majestic SEO, Webmaster Tools, and Ahrefs is probably at best 50% of the total links to a site, and it may be as low as 30%.

I base these statements on my experiences with helping sites recover from link penalties. At Perficient Digital we have helped more than 50 sites recover from penalties this year, and it has happened over and over again that we would help these sites by cleaning out bad links only to have Webmaster Tools report lots of new links the next time it was queried. The reported new links were not new and I have no doubt that Google knew about them before, but simply did not choose to include them in the Webmaster Tools report. However, once we cleaned out some of the bad ones, we got exposed to some more of the links residing in their database.

  1. Ranking Churn: The study was vulnerable to general ranking movement and algo adjustments that our Baseline Pages did not enable us to perceive. This is also a pretty significant risk.

  2. Other Environmental Factors: Let’s face it – what Google uses to rank search results involves hundreds of factors. There are lots of variables that could impact the results. In spite of our attempts to minimize people accessing the content, a small number of people chose to do so anyway. We nonetheless believe that the results have validity for reasons you will see explained below.

Detailed Results

What follows are the raw results for the 3 sites participating in this study. Please note that in all the charts shown here a ranking of 100 really means: “not found in the top 100 results”.

BuyVia Results

The Test Page and Baseline Page tested on this site were articles written by two different users about notable online shopping experiences they had. For the Test Page, we monitored the results for 6 different search phrases.
The most notable result occurred for one particular search phrase, which was a long tail (6 word) phrase enclosed in “”. Note that the use of the “” makes this term even more long tail in nature than it would otherwise be. Here is a chart of the rankings over time for that particular phrase:
BuyVia Test Single Term
This is curious because the rankings got worse for 20 days after the burst of shares and then improved suddenly on August 24th. Since that time the ranking has held relatively steady even after the 4 authoritative shares took place. So what happened with the other terms? Let’s take a look:
BuyVia Test Many Terms
These terms also see improvement on August 24th, but not quite as remarkable a change as we saw for the term previously highlighted.
How did the Baseline Pages do? I have broken that into two charts, simply so the terms that ranked high will be easier to examine, as otherwise the terms ranking in and around the 40th position would make it difficult to really perceive any movement in the terms ranking in the top 5 or so positions:
BuyVia Baseline Low Ranking Terms
BuyVia Baseline High Ranking Terms
The results are pretty intriguing in that they do not show movement on August 24th, but they do show movement on August 31st.

Perficient Digital Results

The Test Page and Baseline Page tested on this site were articles written by two different users about notable search engine experiences they had. For the Test Page, we monitored the results for 11 different search phrases.
As with BuyVia, there was one search phrase that showed pretty dramatic movement. It was also a long tail search phrase enclosed in “”. Here is the detail of the rankings of that phrase over time:
Perficient Digital Test Single Term
On this site, the rankings declined for 24 days after the August 4th burst of shares and then jumped up at that time. Since August 28th, the ranking has held relatively steady even after the 4 authoritative shares took place. So what happened with the other 10 terms? Let’s take a look:
Perficient Digital Test Many Terms
These terms offer a very mixed bag of results, with some of them showing significant improvement on the 28th, and the others being relatively flat.
How did the Baseline Pages on this site do? Here are the charts:
Perficient Digital Baseline Low Ranking Terms
Perficient Digital Baseline High Ranking Terms
The movement on the Baseline Pages occurs on the 29th of August, and it moves in the opposite direction – the rankings drop. In addition, one of the terms on the Baseline Page makes a significant negative move on the 4th of September.

Travel New England Results

The Test Page and Baseline Page tested on this site were articles written by two different users about notable experiences they had traveling in New England. For the Test Page, we monitored the results for 10 different search phrases.
None of the monitored terms showed significant movement as you will see in a detailed look at the data:
Travel New England Test Many Terms
For completeness, this is what we saw on the Baseline Pages:
Travel New England Baseline Low Ranking Terms
Travel New England Baseline High Ranking Terms
No major movement was seen at any time during the monitoring of the results for the test on this site. The Baseline Pages actually show more movement around August 31st than the Test Page terms do at any time.


Our test really had 3 major goals – to see if Google Plus would drive discovery, indexing, and ranking, so I will evaluate that in three independent pieces as follows.


In my opinion, it is highly likely that Google Plus drove discovery of the content. Here is a sequence of accesses to one piece on the Test Pages extracted from the log file on one of the sites:
Log File Sequence
The line items that refer to “+” are Google Plus Sharing events taking place to the content in question (reference: Google Developers site. And, of course, + is GoogleBot. Notice how it takes less than 6 minutes for GoogleBot to come to the page after the first share of the page, and there is a visit by GoogleBot to the site for each share. There are no other accesses of any kind to the content in this time period.
If you wanted to geek out on this in a serious way, you could dig into why it is that GoogleBot comes back to the page 3 times – it’s almost as if the placement in the crawling queue upon a +1 is automatic, without any effort to check if the page had already been visited recently. It appears that there is no de-duping of the crawl queue at this level. But, that is the topic for another piece of work that someone else should do!
What are the possibilities of corruption of this part of the test? In my opinion, they are nearly zero. The log file shows no other accesses to the content between the date of the initial Shares and the visit by GoogleBot. There is a microscopically tiny possibility that someone implemented a link during that 6 minutes, and Google crawled it right at the instant the link was implemented, and that our sources for detecting links have still not seen any evidence of it, but that possibility is low enough to be dismissed.
In addition, the Google Developers page for implementing +1 buttons states the following:

By using a Google+ button, Publishers give Google permission to utilize an automated software program, often called a “web crawler,” to retrieve and analyze websites associated with a Google+ button.

While this does not say they will index it, or rank it, it does say that they reserve the right to crawl it, and it was important enough to them that they explicitly stated that they might do so.


Initial shares of all six articles (3 Test Pages and 3 Baseline Pages) were completed on July 19th. All six articles initially appeared in the index on July 29th – 10 days later.
We first discovered that the pages were indexed via daily manual checking using a search query similar to this: “[insert long tail search phrase here]”

The “” were part of the search phrase, and each of the phrases tested were long tail queries that did not match up with other pages on the site being tested.
Once we saw that the pages were indexed we re-checked to make sure that the pages had not received any links, and no links were found to any of the 3 pages. This does not mean that the content received no links, only that the collective data available to us from Google Webmaster Tools, Majestic SEO, Open Site Explorer, and Ahrefs showed no links.
As mentioned above, my guess is that these tools cumulatively may reveal only about 30% to 50% of the links to a given website. So there could be links to the pages from other sites that we did not see. To help minimize this as a potential source of error, we also checked incoming referrers to see if the test pages were getting any traffic from other web sites, and none was found.
Other possible sources of corruption exist. At one point Matt Cutts did suggest to me that visits to the pages by browsers with SEO toolbars installed could be a potential problem. What those toolbars may do is unpredictable. During the period after the initial GoogleBot visits on the 19th of July, there were a handful of people who appeared to have visited the page with a browser. Some of these did occur prior to the confirmed indexing of the content.
At least one person dropped one of the pages into a Flipboard magazine, so we did see visits from a Flipboard crawler from time to time to some of the content. Based on the checking I have done so far, I do not see evidence that these Flipboard pages are indexed, so I don’t think that Google would have used those links to drive indexing, but I welcome corrective feedback from Google on this point.
I do not think that once the page was discovered that incremental browser accesses would be a significant factor in causing a page to index, regardless of the presence of an SEO toolbar. It is possible that such SEO toolbars could cause additional exposure of the page to Google via the Google+ API, but such additional accesses would only reinforce the notion that Google+ can help a page get indexed.
One other point of discussion is the long delay between the shares and the initial indexing. Clearly, the discovery of the page did not result in immediate indexing. Why did it take 10 days? We all assume that Google captures Google+ data in real-time, but this indexing delay looks more like crawling behavior. However, the fact that all 6 pieces of content indexed on the exact same date leads me in a different direction that suggests some level of “Sandbox” type behavior.
Another observation is that during a 10-day timeframe that on higher activity Google Plus accounts posts get pushed down the stack fairly quickly. Once a post has 10 other posts in front of it, does Google count that the same way? We don’t really know.
But, in summary, with the information available to me, I don’t see any other signals that would have caused the posts to be indexed.


Once we saw that a page was indexed, we were immediately able to find search queries for which the page ranked. However, this does not mean that the shares were driving ranking. As per the original Sergey Brin – Larry Page thesis, each page on the web has a small amount of innate PageRank. This PageRank by itself might cause a page to rank for certain types of long tail queries, even in the absence of any other signals.
In addition, a page with no links may also gain some benefit from the overall authority of the domain on which it resides. How this works exactly is not known outside of Google. However, it is clear enough that we need more data to be able to conclude that we would see ranking benefit from G+ shares. This is the reason we sent two additional waves of shares in the direction of the pages being tested.
It is also important to note that the risk of undetected corrupting links goes up over time! If you believe, as I do, that the available tools only give you a portion of the total link graph, the chances of malicious behavior by people who become aware of the test, or people innocently making stupid mistakes goes up. In addition, as stated before, general rankings churn, and larger scale algo changes can enter into the mix.
That said, to me, the most remarkable thing about the data in this part of the test is how unremarkable it is. For two of the sites, we see some things initially moving in the wrong direction, and then moving up in the rankings but only after a long delay, and the Baseline Pages moving on different days. For one of the sites we saw no material movement at all. Based on this data, this study did not show any material evidence of Google Plus Shares driving rankings movement for the Test Pages. Read more on my thoughts on this in the summary below.

Don’t Correlate Me Bro?

Most of you have seen the correlation studies. Both Moz and Searchmetrics have some excellent work in this area. The net is that social signals, such as Likes, Shares, and +1s have a very high correlation with higher search rankings. Surely that proves that these things drive search rankings, right? They do not, nor do they actually claim to. It is important to remember that many things can be behind a correlation. Here are a few examples of interesting correlations:

This Item Strongly Correlates With This Item The Real Cause
Eating Ice Cream Drowning Deaths Both happen when it’s hot out
People Who Dislike Horseradish Say They Do Not Have an Above Average Libido No idea! (Source:
Use of Internet Explorer US Murder Rate Pure coincidence (source: Buzzfeed)
Shares, Likes, +1s Higher Rankings People socially share content because it is good, the same reason why they might link to it

That conclusion is an important one. Producing great content will “cause” some strong correlations, because people like to share great content, be it by link, or via social site. Of course, the correlation is strong. To help speed you along to accepting this conclusion – Google can’t even see who Likes a particular piece of content, so clearly that is not causation in action.
So are correlation studies bad? Not at all. In fact, they offer tremendous value in helping us understand web behavior. These particular studies remind us of the critical link between great content, online reputation and trust, and getting results in both search engines and on social media sites. The fact is that these things are inextricably linked, not by one causing the other, but because there is a common set of behaviors that will cause both. You can summarize some of the desired behaviors as follows:

  1. Create great content
  2. Build relationships with influencers
  3. Build relationships with communities of like-minded people
  4. Strive to help others out

You can add your own to the above list if you like, but you get the idea.

What About the PageRank Flow in Google Plus?

Why would Google allow PageRank to flow in parts of Google Plus if it did not intend to use it? This study does not prove that they don’t use it, and in fact, I believe that they do use it, just not the same way that they have used traditional web links. A couple of areas where this PageRank could have an impact are:

  1. You may have seen Google+ content in your search results. Google Plus posts made by people with higher PageRank profiles may get more rapidly indexed than by Google Plus posts made by other profiles.
  2. A higher PageRank of a Google Plus profile may increase the likelihood that those posts will show up in the personalized search results for people that follow that profile.

Mark Traphagen did an excellent write up of Google Plus driving personalization that you can read for more information on this topic.
But why would Google not use the PageRank in Google Plus Shares to drive ranking? I believe there are three answers to this question:

  1. It would be too easy to game – Google does not want people running around sharing content with SEO as their goal. I believe that Google Plus provides a tremendous amount of valuable information to Google about the preferences of people that can provide significant enhancements to their personalization algorithms. Put simply, bad SEO link building behavior would mess up the value of this data source.
  2. The data is probably too sparse – yes we all think it is this huge mountain of data that they can use, so they must be using it. Certainly adoption of Google Plus is growing rapidly. There are many people who do a LOT of posting on G+. But there are far more people who do not. Even in the SEO industry a significant number of people are not at all active on Google Plus.
  3. Google Plus Shares don’t require the same level of effort as implementing a link on a web site, and they don’t involve as much commitment – on an active profile that Share has scrolled out of site within a few days’ time.

Endorsement Commitment Chart
As human beings, we are all inherently flawed. In the search industry, we have a strong tendency to assume that our belief that Google could leverage a signal as a ranking factor means that they do leverage that signal. The problem is that speculating that something is a great ranking signal is different than figuring out how to effectively use it. Whether or not a source of data makes a good ranking signal is ultimately determined by a combination of highly sophisticated mathematics, and lots and lots of real-world testing.
The reality is often quite different than the speculation. It behooves us, myself included, to remember that. The correlation studies actually give us fantastic information. Information that does not suggest we pursue manipulative behavior, but in fact suggests that we pursue world-class content marketing as a core business strategy.

Summary Commentary

Here is how I would sum it up:

  1. Google+ shares do drive discovery.
  2. Google+ shares probably drive indexing as well, with some possibility of error in this stage of testing (links we don’t know about).
  3. We saw no evidence of Google+ shares driving ranking.

It is also interesting that Google Plus shares do not appear to exhibit a “Query Deserves Freshness” (QDF) behavior. If a social share was treated as a potential indicator of news as you might expect a very fast indexing response with initially higher ranking that declines over time would be what you would see. Yet, our Test Pages took 10 days to appear in the index. This is clearly not breaking news level behavior. If Google+ is used at all in this fashion, it would probably require a much bigger burst of activity of social shares for QDF treatment to happen, and it may require the support of links elsewhere on the web.
Our test was designed to eliminate distracting signals, and hence we did something that in its own way was a bit unnatural. We attempted to minimize and in fact eliminate re-shares. Our text description of the articles was not normal – in fact, it was a warning to others to not look at the content. We needed to do that to try and get as pure measurement. In addition, every share of the content used the exact same descriptions, which is also somewhat unnatural.
These constraints could possibly impact the validity of the findings. In addition, other behavior patterns, such as organic re-shares, comments, and other activity could help improve the results. But, ordinary web links do not depend on comments and re-shares to carry weight.
My opinion is that if there is any impact from links in Google Plus shares, that these links do not get treated the same way a regular link does even though we can see that links in Google Plus pass PageRank. For purposes of this discussion, and for the study, we are not talking about “personalized” results. That is another matter, and Google Plus Shares by people you know do impact the personalization of your results.
Google can filter link signals, including those in Google+, at many levels. Why would they allow shared links to pass PageRank if they did not want to use that PageRank in some manner? I believe that they want to use it to help them identify more authoritative profiles. Many people believe that more authoritative Google Plus profiles will have their posts indexed by Google more quickly.
Many of you will also have seen Google Plus posts in your web search results, and these generally come from people whom you are following. It may be that you are more likely to see such results more often for people who have more authoritative profiles.
As for treating a Google+ Shares the same way they treat a traditional web link, remember my theory that a Google+ share does not involve either the same effort or the same commitment as a traditional web link which is harder to implement and is more permanent.
I acknowledge that there are many ways to point at the holes in this study, and I have offered my interpretation of it.
There are smart people I know who have seen this data who disagree with my interpretation. Are you one of them? Let me know via your comments and feedback.
The people who performed shares of our content played a key role. The following chart shows the PageRank distribution of the people who participated in the first two waves of shares:
PageRank Distribution
The hand-picked participants who executed the shares in the first 2 waves of this study were:

Participants with authoritative Google+ profiles that provided shares were: David Amerland, Ronnie Bincer, Andrij Harasewych, and Mark Traphagen.
The contributions of these people can’t be minimized as they all put somewhat unusual posts on their Google Plus profiles, and their help was critical to this test!
There are others who deserve recognition for their assistance in earlier phases of this study. In my initial studies, I had many engaging discussions with Marcus Tober of Searchmetrics, and these helped me conceive this latest edition. In addition, two other sites participated in earlier versions of the study: Extra Space Storage and Amsterdam Printing.
See all of our social media and SEO studies!

Thoughts on “Direct Measurement of Google Plus Impact on Search Rankings”

  1. Thank you very much Eric Enge and all people who are involved in this study. Thank you Marc Trapenhagen for sharing this article on Google+. This is the most detailed study about the relationship between Google+ and ranking in the Google search engine. You have given as much information – it will take now a whole night to evaluate this. I would like to translate later the key content and make available to the German community. Thank you all for your great efforts.

  2. If an author doesn’t understand algorithms (and how to write one himself or herself) and doesn’t have experience as a DB systems analyst (because Google is a DB), then this isn’t “research” as much as it is wild speculation.
    The experiment is not-thought-out the way an algorithm programmer would do it.
    Does it make sense that Google+ and shares would help your rankings? And the links they create from Google+? Hell yeah. Of course it makes sense. That makes sense, but Google doesn’t want it to be that easy. So they are going to build something into the algorithm that adds authority to the votes and shares. Maybe not something very obvious.
    A million things pop into my head as to why this is thoroughly flawed.
    1. The test lasted for a few months? What if Google plusses need to be seasoned? What if they get their power at the 6th month? Seems incredibly simply to me, but just that one simple idea essentially makes the experiment only “As We Know It, Based On Three Months, And Without Considering Seasoning to Add Authenticity.”
    2. What if there is something else- or a series of something else’s- that needs to occur…to trigger a deepl-nested subroutine, that makes the plusses and shares go from zero value to very valuable? This is why I say “a million things”, because it could literally be a million things…
    What if, for example, a plus didn’t count if the people bounce from the page in 2 seconds? That would appear to be a bogus plus. There has to be some authenticity in the vote itself. I can think of many things that could add authenticity to the plus– rather than the user. Or a combination of the two.
    For example, in order for a plus to count as a rank-building plus, the person who plusses the page has to click on one other page in the site? (lowering the bounce rate and proving that the front page plusses aren’t being paid for and have real END USER VALUE.)
    And what if it goes many levels deeper than that? A series of specific actions calls that subroutine- which, in your experiment, you never even dreamed of triggering- but to an algo programmer might be common sense. A piece of code that is triggered (or more accurately “called”) when a certain specific event happens.
    It is common sense to believe that plusses would help ranking and I know they’ve helped many of my sites. Of course, I earned those plusses naturally and it didn’t happen in the confines of a 3 month vaccum.
    I didn’t do an experiment with them; common sense just happened and I acquired them without any time constraints and without a certain set of predetermined people.
    I think you’ve really missed the ball here. Correlation does not equal causation, and that’s the biggest mistake people make in SEO. They always have and they always will I suppose.

  3. Eric;
    Thanks for the causation study that you have concluded,
    – However I’m sorry but it’s not that i will say that its wrong but i see this study to be missing a key element – which at the same time is the hardest to study in order to see causation.
    The ‘ranking engine’ (the algorithms of algorithms of algorithms that use larry page’s rank as well as all other signals) of most Search engines work in a tie-breaker fashion, where some of those rules will only trigger when your page triggered many triggers, then they can set a specific signal to work better than others by creating a tie-breaker rule.
    Google+ shares and +1’s is a compliment tie-breaker signal to your page. It’s not a trigger and so your study will not show any causation to your results, as you have shown.
    Eric thanks again for your study.

  4. Hi Michael – if you read the above carefully, I pretty explicitly note that there are plenty of ways to poke holes in the approach that I used, so I agree with you that there is plenty of potential for G+ to influence search results in ways outside the constraints imposed by the approach I used.
    The most important constraint I placed on what I did was trying to eliminate the possibility of the test articles receiving links, because that would immediately invalidate the test.
    As for G+ being a platform of value, while I became active only about 5 or 6 weeks ago, I am all in. I am a believer. The main thing I believe though, as a result of this test, is that the way that Google may be using shared links as a signal in a different way, i.e. with additional filtering, than traditional web links. I think this agrees with what you said above as well.

  5. First I would have to say that not having at least one link to the page(s) will skew the results.
    I have done a similar test and found that a G+ share caused a page to jump from a baseline of a #24 position to a #1 listing.
    This was only a temporary jump which stayed for about 9 days.
    Were results tracked manually or was a program used?
    If a program to check results was used on a daily basis, the drops could have been caused by breaching Google’s TOS which forbids automated queries.
    Shares might have been seen as faked, due to the fact that visitors did not actually visit the pages themselves.
    Shares might also have been seen as faked if they were outside the normal share profile for the site.
    This could be the reason for the drop in position.
    You state that
    “the study methodology was designed to maximize the chances that the Google Plus Shares were the only possible factor that could result in content discovery, indexing, and/or rankings changes for the Test Pages.”
    This would be outside a normal use/profile of a page that is likely to be shared.
    If the page did not have a regular link there would be no PageRank passed.
    How could the baseline pages have ANY rank given that there were no links to them and no shares?
    How did Google find these pages to index them?
    You also state:
    “each of the phrases tested were long tail queries that did not match up with other pages on the site being tested.” but earlier you stated:
    “The articles we had written for the study contained content which was highly relevant to the site on which it was placed.”
    So how could the queries be relevant if they did not match up with any other content?
    I think you need to redo this test with pages that have obtained a stable position and see if (minimal) sharing in accord with the site’s overall share profile causes an upward movement.

  6. Reg – actually, if you read the above clearly, we did have the pages in stable ranking positions for a number of search terms after they were indexed on July 29th, and then we waited to send a burst of additional shares until August 4th. It is after August 4th that we are measuring the results when we talk about ranking.
    Also, I do discuss in here that every single page, even without any links is borne with a small amount of innate PageRank. In addition, pages can inherit some authority from the domain on which they reside. This is what drives initial ranking.

  7. Great study. Interesting that it actually took 6 days for those pages to get indexed. From what I’m seeing, pages are getting indexed a LOT quicker than 6 days. One thing you didn’t mention (or maybe I missed it) is whether or not those page had any internal links pointing to those pages on the site (which I’m guessing they didn’t).

  8. Outstanding analysis Eric, thank you for doing this work. Nothing here invalidates what I tell clients, which is “do the right thing and don’t worry about manipulation.” So – produce the best, most relevant content you’re able to for your market. Build connections and relationships across social networks (Google+ being one, though not necessarily the most important – depends on where your customers and prospective customers hang out), and share content with the goal of providing value to your connections. It takes sophisticated analysis (as shown by the work you’ve done, as well as, ahem, other sources which may have prematurely confused correlation with causation) to show whether such activities lead directly to higher search engine rank or not, but – they are the right things to do regardless in terms of increasing overall web presence and driving online business results.

  9. Simply the best research done on search and social ever and their correlation! As one that reads everything and puts food on the table and a lot of it from SEO I thank you for the work!

  10. Thanks for the info. From what I am concluding, google+ shares, by themselves, do not count. But, because they are too new to be trusted as a sole indicator, they have to be included with other factors in order to count. Combine those shares with other indicators, like internal links, for example, and those +1s DO count, a whole lot.

  11. While I appreciate the study and the hard work behind it, I’m surprised anyone thought that “shares in a vacuum” would be enough to affect rankings in any significant way. I agree with Reg when he mentions that this might even be looked upon as fake shares, since visits to the pages were essentially non-existant. One signal alone, in my opinion, is more likely to harm than help. Sure, it’s near impossible to run a true test with many (natural) factors involved, but it’s the combination of factors that makes Google’s algo what it is. Still, the work behind it is definitely appreciated. If nothing else, it encourages fruitful discussion.

  12. Can’t argue with that Eric! Pretty conclusive, although I guess things could change in the future.
    I think point 1 of the reasons why they wouldn’t use + shares as a ranking factor sums it up – it’s too easy to game.
    Funnily enough I was reading an article just this morning, which took the view that shares should give a decent boost to your rankings. I’ll have to go back to it and point the author here.
    Actually I just had a thought…
    I think we are all agreed about the importance of a diverse link profile, so lets say 2 sites had exactly the same amount of regular inbound links (excluding g+) and (although I hate to use the phrase) pagerank. Do you think the g+ shares might at that point come into play as a ranking factor? A boost for link diversity/social proof?

  13. This is a really excellent piece. As a marketer I’ve never understood this industry’s fascination with gaming social networks for the purpose of ranking better in search. I think you’ve nailed the correlation between more traffic and social posting with the intersection of google+ posts displayed for personalized searches as part of their blended experience.

  14. I am wondering if the Google Search correction that started the 3rd week in August could have skewed the results. This is a tremendous piece of research. Thanks for going to all the work.

  15. Not really. Matt provided some very limited input on flaws in our original study, and that caused me to make some changes to the methodology, but he had no involvement other than that. Once he outlined the flaws in my first pass, they were pretty apparent to me as issues I had to address.

  16. Hi Ann – In fact in my write up I speculate that it may have caused that ranking movement at that time.

  17. It might. Many are speculating that the isolation of the shares killed their value, and that sharing would have an impact if the page was also receiving links.

  18. Hi Donna – I tend to agree with you, but there were many that thought differently, and hence the purpose of the test!

  19. Thank you for your hard work. Impressive ! I understand the critics but at least we have, thanks to this study , an idea of where we need to push the effort. Yes, we might disover later that +1 impact ranking in an unespected way but at least we know now it doesn’t really do anything in a “straight forward way”. In some context, getting +1 is not easy. It requires lot of energy and time invested to get some. If we know that all this energry is almost useless in terms of ranking, let’s focus on something else. Thanks again again for sharing this work !

  20. First, Eric, I would like to commend you on this study. It’s not everyday that you see SEO’s doing causation studies rather than correlation ones.
    After putting some thought into your study, I’ve come to the conclusion that it is incorrect. Google +1’s do impact search engine rankings. In fact, you called out the fatal flaw within the first five paragraphs: “In our study, and in my opinion, Google Plus Shares did not drive any material rankings changes (of NON-PERSONALIZED RESULTS) that we could detect. This study has completely missed the entire intent of Google: focus on the user.
    By “focus on the user” we know this to mean tailoring search results based on user experience, device type, geo-location, social signals, and past interactions if you are logged in. By taking out the personalization of search results, he failed to study the true power of Google +. You see, Google + is the fastest growing social network- outpacing both Twitter and LinkedIn. It has over 360 million active users and adds 625,000 new users every day. The astonishing things is, slightly more than 60% of people logged in daily. This means that there are roughly 216 million personalized search results every day- assuming they only make one query. We know Google collects a massive amount of data on every single user: from every email you ever sent or received in Gmail, to every Google alert or conversation you have had over Google Talk. Google can even track searches on your computer when you’re not logged in for up to 6 months!
    How would those rankings have changed if they were checked via the people within the circles those pages were shared? It is a well-known fact that Google uses social signals to tailor search results, so one would assume that if there were some social influence on these pages from connections on Google +, they would have even a minor impact on search rankings for these pages. Also, just to point out the obvious- how would those pages rankings look for you (Eric) as well as the overall site’s rankings after the share? My guess is they climbed pretty rapidly in his personalized SEPRS.
    You studied the effects of G+ as a manipulation tactic rather than a ranking factor. Google is trying very hard to push the utilization of its social network, which is the key to using it to achieve higher keyword rankings for that particular end user. We need to focus on getting people to use the social network if we want to rank highly for the individual’s given query.
    Does Google + work as a manipulation tactic- no probably not. Does it count as a ranking factor? Well, I can’t say with 100% certainty, but more than likely- we need additional testing within personalized SERPS to truly understand it.

  21. Bill – thanks for your long and thoughtful comment. I don’t consider that a fatal flaw at all. There are many people out there telling others that G+ links DO impact non-personalized rankings. I am seeking to address that notion. Also, bear in mind that personalization is far from ubiquitous. Under normal circumstances, a brand with 100,000 followers has the opportunity to influence the results for – a 100,000 people. There are a lot of other people out there!

  22. Eric, I’d love to see a study done within personalization. I wonder if a brand with 100k G+ followers has the ability to influence the results for far more than those 100k people. What about the people in their circles? Google has the ability to understand both relationships between people and between websites. If person A and person B share are connected in a circle and enjoy similar content, would rankings improve for a website for person B if person A shared their content? We need more studies like yours to truly understand its power. I’d love to see this replicated but for personalized results somehow.
    Really I have more questions than answers at this point and a lot of speculation.
    Also I’ll agree with you that there is a ton of mottled information out there on G+. Thank you for being the one to do a true investigation and shed light on the subject.

  23. I’ll also disagree with the fact that a brand with 100k followers can only influence 100k people. Lets examine Facebook for a second (sine thats G+ main competitor). A Brand on facebook with 100k likes has the opportunity to influence far more people. If Person A is friends with Person B, and Person B suddenly likes a Facebook page, that “Like” will appear in Person B’s timeline. Social is exponential- the network medicine principle states that a single message will typically be spread 7 levels deep throughout each persons social circles- which I think can be loosely applied to social networks.

  24. Bill, Fair enough! But, it clearly does not reach everyone, not even everyone with a Google account. Like you, I have more questions than answers, and an awful lot to speculate about. Thanks for your feedback!

  25. Michael, it seems like you have quite a bit of knowledge in this area. It would be helpful to understand how you would structure SEO tests, so we can all get better at this. Personally, I think Eric has done a good job (most studies can be poked at), and done a service by releasing the results.

  26. Nice research and great analysis, I must say. I believe the rankings were global without any Google+ influences in search results.
    What about the effects of search results for those profiles or Google+ users in the same circles? Does it get better?

  27. I’ve often wondered just how much Google+ influence there is transferred to your domains organic search.
    Thanks for sharing Eric.

  28. Very good research, I think that Google+ has an impact on your rankings, maybe a small but still. I think that Google+ will have even bigger impact on website rankings after couple years.
    Nice article, Thanks.

  29. Nice post. I think that Google+ has a big impact to search results and it will only increase over time.
    Very nice research, Thanks

  30. One of the best and most thorough studies on the impact Google+ has on search results. At the end of the day, getting your audience to ADD you to a Google+ Circle is very important, mostly because once you’ve been added to a Circle, your content and pages have the advantage of showing up in the SERP’s so long as the persona doesn’t hit the globe and hide personal search results, which my experience shows very few people will do – if they even know about this option.

  31. I like to read studies through what I call “the idiot lens.” I barely know what Eric Enge is talking about. I get the general meaning of “causation” and “correlation.” My input is this: I will never, ever know how a “+1” affects a search algorithm. What I do know is that until businesses can quantify that “x factor” that a “+1” embodies, money is being wasted.
    What I can add came about today, after I visited my Yahoo account after a two-year hiatus. I despise flashing adverts. I am too old for them. Handing out a plus on G+ is the kind of social shorthand that I really enjoy. The companies that capitalize on this first will be the ones who figure out how to interpose themselves on the G+ demographic in a way that is as subtle as a “+1.”
    If the idea behind these studies is to discover how much a +1 is worth, shouldn’t a study be undertaken (not by Eric–he seems to want some time off) to determine what the impact of a +1 by a target demographic member in and of itself does for a page, product, post, brand or service?

  32. Well I don’t really know how this G+ works but I just know that it does. I have tested it, by making a campaign and it did have a impact on my ranking, because at that time I didn’t do anything else. Just the G+ campaign.
    Thanks for the post.

  33. The google plus was pulsing the rankings till it was pulled back due to abuse by many. I think spammers have to refrain from spoiling all this. G+ was a great ranking factor and genuine ones would have been great.

  34. Even without any evidence of DIRECT impact on rankings, Google+ will undoubtedly drive additional traffic and indexing, which will add some definite positives for search purposes.
    Many SEO professionals “assumed”: that Google was going to weight it more highly, and that does not seem to be happening. However, with Facebook throttling the heck out of non-paid posts, Google+ is an excellent alternative– though it is just one of many at this point.

  35. Amazing writeup – nobody else goes into quite so much detail.
    The day Google uses G+ shares and the like to directly affect SEO rankings is the day I loose all trust in them and their services. Thank you for your efforts!

  36. Eric I think I enjoyed reading all the comments here just about as much as the article itself. There is no doubt that this is a fascinating topic that I am sure will be debated over and over again in the world of SEO and social over the next year. I really liked Michael George’s analysis of possible seasoning with social signals. Without conducting any studies like you I have noticed that my blog articles slowly rise in SERP over time and I am guessing the signals possibly could be playing a part in that.

  37. Hi Bill – of course, the study measured the use of Google+ sharing links to a web page in an environment where those pages received no other signals! So it is still possible that G+ signals working together with other signals have an impact today – we did not test for that in this study. However, that said, I am still of the opinion that this is not yet the case either. Check out this video to see what Danny Sullivan had to say about Hummingbird and how part of that platform change by Google was intended to help them process social signals.

  38. I’ve had my social page rank higher and faster than my actual website. And no I always make sure I’m logged out of Google, the cache is clear and I’m using a private window before I search. When I make a new site now I always make the social pages along with them. I’m convinced it helps you get indexed and ranked faster.

  39. Hi Christian – this study focused on shares. What I can tell you though is that links to author profiles do pass PageRank, and that does mean that they can pass authority to the profiles.

  40. I’m not sure if G+ had impact on rankings but it sure did on clickthrough. Just like with almost everything that is different from usual (like video snippets, Google map snippets etc.).

  41. Hi,
    I am a SEO Consultant and I have seen several times that indeed Google plus has a positive impact on search rankigs.
    greetings from Spain! (and sorry for my english 🙂 )

  42. For the past 6 months I have done a small test with Google+, well it wasn’t as big as yours here, but the results definitely shows that Google+ posts have an impact of specific url rankings.
    I dont know exactly how big the impact is, but as far as my research shows it has bigger impact then other social media. Im not an SEO expert, but I can even see that PA grows faster for those URLs that has been shared on Google+.
    Nice research by the way Eric.

  43. Great research thanks and excellent data but I’s like to add it is still missing one other key factor which is user relevance and authority.
    Not every +1 or share is valued the same – authority and relevance are a huge factor in how Google rates you posts.
    Have seen ranking improvements when the above has been taken into account albeit temporary.
    This is a very good test, would like to see what happens with a different set of followers with higher authority and relevance to the destination pages.

  44. Very good information, it is logical that Google plus is important in the ranking of Google, but will this be a factor in this ranking in 2016 (?)

  45. Alex, if you’ll read our study carefully, you’ll see that our conclusion is that Google+ had no discernible impact on search rankings at all. Where it does have an effect is personalized search. If you are logged in to your Google account and do a search, if there is relevant content in a Google+ post by someone or a Page you have circled, it can get elevated to your first page results.

  46. It only makes sense that G+’s will have an effect on ranking. It is a Google property. Just like it is easy to rank a YouTube video which is also a Google property.

  47. For years we have been told of the importance of social shares yet this evidence and the experience of others suggest that social shares like those on google plus are not important compared to other factors. I am not even convinced google plus is all that important.

  48. Still limping along with a samll cadre of passionate users, but defintely not mass market.

  49. I think it’s less likely for people to go for google as a sharing platform. Twitter and FB work better that ways. But i do believe google plus affects ranking more. Its harder to get a great author with high G+ authority to write for most of us

  50. Hi Carlos – as this point, there is no indication that Google+ is being used as a ranking signal in any way shape or form. It can still help you get your content discovered and crawled by Google, but it’s not a ranking factor.

  51. I was commenting on this topic with some colleagues and I research about before I found this site. This is a great analysis and I regret I did not read it before in the past years. Do you think this is still applying? Google plus has been really damaged and forgotten in the past few years and I’m not sure if Google is still using it anymore.
    Recently I did a test why a site ranking in page 5 opening just the three basic social media accounts (TW, FB and G+) and posted some random content linking to the site and it automatically ranked in less than 10 days to page 2 with no other improvements. I’m not sure to what extent do Facebook and Twitter also have influence over the algorithm. I’m sure that FB is really important, but not so sure about TW.
    And maybe, if I did that isolated with the G+ account maybe I could have found out a surprise.
    I’ve read some of the comments and despite most are pretty old, I would like to see if this can be repeated somehow in the future maybe with new metrics and a new research framework.
    Thanks for the info!

  52. We don’t test this anymore because Google has been quite clear that they do not use any links from social networks as a ranking signal. They give good reasons for that. In addition, no one has shown any convincing evidence (convincing meaning from a carefully controlled study; not one-off anecdotes) that this has changed.
    As for your experience, content can rank on Google without links. Links remain a very high ranking factor, but they are not the only factor Google uses for ranking. If the content is high quality, relevant to the intent of the query, and from a trustworthy source, it’s not hard to get it to page 2. Now getting to page 1 is another matter! In most cases it has to be exceptional content and have a good link portfolio. See our video with Google’s Gary Illyes about how content can rank without links.

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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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