You can’t throw a stone in SEO without hitting a link builder.

Since Google’s earliest days, links are – and have always been – an integral part of search optimization.

But what about outbound links?

These are the links in your content (the source) that point to a different website (the target).

But are outbound links actually a ranking factor?

The Claim: Outbound Links As A Ranking Factor

Google sees links from one site to another as a sort of endorsement.

When one site cites another via a link, there’s a fairly good possibility that they’re doing so because they believe the content they’re linking to is reputable, authoritative, and trustworthy.

Is that always the case? No.

As long as there have been search engines and links, marketers have been trying to find ways to manipulate Google’s perception of what a link actually means.

We know that when a site links to you, it can help improve your search rankings.

But what about when you link to another website – can that help your site rank higher, too?

The SEO industry has never entirely come to a consensus on whether outbound links are a direct ranking factor in Google’s algorithm.

Many believe outbound links aren’t a ranking factor at all and have no SEO benefit to the linking party (the source).

However, some believe that who you link to is a signal that can help your own rankings, as well as the page that earned your link.

The Evidence For Outbound Links As A Ranking Factor

Google’s John Mueller addressed that very question in the inaugural Ask Google Webmasters video in July 2019. He said:

“Linking to other websites is a great way to provide value to your users. Oftentimes, links help users to find out more, to check out your sources, and to better understand how your content is relevant to the questions that they have.”

In the same video, Mueller cautions that the reasoning behind the link matters – and Google is pretty good at sniffing out bad links.

He calls out reciprocal links, paid links, and user-generated comments as types of links that Google may see as of dubious quality. For these links, you should be using rel=”nofollow.”

See Julie Joyce’s guide, When to Use Nofollow on Links & When Not To, for more on that.

In short, Google wants to see outbound links that indicate you think the page you’re linking to is a great match for users.

So, we know that user experience and the value provided to searchers/site visitors is Google’s top priority.

As Mueller said, outbound links are a great way to provide value to users.

Plus, we have a bunch of other SEO pros and blogs saying things like:

• “…valuable outbound authority links are part of what Google likes to see as part of its recent Google Panda update.”
• “By adhering to some of the following best practices when optimizing outbound links – you could be seeing an effect on your visibility and ranking.”

Some even quantify what you need to do for outbound links to “work” and recommend including at least two or three per piece of content.

(I’m not linking to those sources as I don’t want to lend them our credibility. See how that works? Suggesting in 2021 that a certain density of outbound links is SEO magic makes about as much sense as optimizing for a keyword density of 7%.)

Aside from the industry chatter, Shai Aharony at Reboot did a small experiment in 2016 in which his team created 10 brand new sites with articles “of comparable structures and text length” to test whether outbound links influenced ranking.

The study got a bit of attention following an endorsement from Rand Fishkin, who said,

“This study of outgoing links impacting rankings is as close to ‘proof’ as we get in the SEO world…”

Half the sites contained three links – one each to Oxford University, Cambridge University, and the Genome Research Institute. Two used the name of the institution as anchor text; the anchor text for the third was the completely made-up test subject word “phylandocic.”

Another made-up control word, “ancludixis,” was placed in the content unlinked so they could determine whether the anchor text was a factor in ranking. All domains were purchased at the same time, and none were optimized for “phylandocic.”

The study declares:

“The results are clear. Outgoing relevant links to authoritative sites are considered in the algorithms and do have a positive impact on rankings.”

The analysis goes on to say:

“The main thing to take away from this test is that although we don’t know and have not proved how powerful outgoing links are in the grand scheme of things, we have proved they do have a positive impact if used correctly.”

However, this evidence is not exactly convincing.

Here’s what we see in the results. The author notes that the graph shows the position of the sites in the ranking.

• Blue line = site with an outgoing link.
• Orange line = site without outgoing links.

As you can see, the sites with the outbound links ranked in the top five Google results and those without in the next five.

Without seeing the content itself, it’s impossible to know whether there are other factors at work.

But we do know that the made-up target keyword, “phylandocic” was used as anchor text once in at least each article. Did it increase rankings because it was anchor text, or simply because the word appeared on the page?

This test is simply too small. The fact that there’s no other content in Google’s index about this made-up word pretty much ensures you’re going to get the top 10 results with 10 articles.

All other things being equal – and it does seem they took steps to make all other things as equal as possible – this could just be a matter of the additional keyword mention making those articles more relevant to the query.

So does this actually prove anything about the value of outbound links as a direct ranking signal? No.

The Evidence Against Outbound Links As A Ranking Factor

Outbound links can tell Google a lot of positive things about the site the link is pointing to – that it’s considered authoritative and trustworthy, for example.

Or that the person who created the content is an expert in the field.

That’s exactly what Google wants to see in the content it recommends as answers to searchers, and they tell us that throughout Google’s Search Quality Raters guidelines.

Get your free SEJ Guide to Google E-A-T & SEO to learn more about that.

But Google also has to consider that there are a lot of ways links can be manipulated. They’re a commodity that can be bought and sold.

People can exchange links for other links or for anything of value to the parties involved – for a free product or discount on services, for example.

Links can even be placed on a website without the owner/webmaster’s knowledge via code or URL injection.

There are a lot of different ways links can be gamed. Outbound links, in particular, are troublesome as a search signal.

Couldn’t I just link to a bunch of highly authoritative, popular sites in my niche and that tells Google I’m one of the cool kids, too?

At one point, you could. This PageRank sculpting blog post by Matt Cutts resurfaced in a 2019 Twitter conversation about the benefit of linking to authoritative content.

A user asked Mueller whether the conclusion made in a graphic that cited “multiple SEO experiments and studies” was true.

Despite the fine print making it clear that the studies found correlation and not causation, the piece made a bold statement. And Mueller was clear in his response:

No

— 🐄 John 🐄 (@JohnMu) December 29, 2019

Here’s where the aforementioned PageRank sculpting post comes in:

Hey @JohnMu, in Matt Cutts’ tenure, he told us repeatedly that outbound links were beneficial. For example, in this blog post (https://t.co/hx6I5LhLaD), he states: “parts of our system encourage links to good sites.”. Can you help reconcile the contradiction?

— Corey Northcutt (@corey_northcutt) December 30, 2019

But here’s the thing – that Cutts post is from 2009.

Search is constantly evolving. It’s not a “contradiction” that the advice from that time would be different a decade later.

The issue came up in 2015 when Mueller responded to a Webmaster Central viewer question about any potential benefits of linking to one’s trade association websites:

“We would say there’s not any SEO advantage of linking to anyone else’s site.”

And again in a 2016 video where Mueller was asked:

“External links from your pages to other sites – is that a ranking factor? What if they’re nofollow?”

He responded:

“From our point of view, external links to other sites – so links from your site to other people’s sites – isn’t specifically a ranking factor.

But it can bring value to your content and, in turn, can be relevant for us in search. Whether or not they’re nofollow doesn’t really matter to us.”

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Google Search Liaison Danny Sullivan echoed this advice, that the value of outbound links is for users. This was in a series of 2019 tweets, one of which advised that SEO professionals should think of them in terms of journalistic integrity:

I’d think of linking as just part of proper attribution. You’re a journalist. You write a story, you cite your sources. If those sources are online with more info for the reader, that cite should link to them. That’s just good journalism. It should be standard….

— Danny Sullivan (@dannysullivan) October 16, 2019

And this is where outbound links really shine.

Used appropriately, outbound links can tell Google things like:

• You’re aware of which people and websites in your industry are considered authoritative and trustworthy because you’re an active member of the community.
• You’ve done your homework and invested time in truly understanding the topic.
• You value multiple perspectives and are doing your best to present fair, balanced information to readers.
• You care about accuracy and it’s important to you that the information you reshare has been fact-checked.
• You value readers’ trust and want to ensure they can verify your statements if they choose.

These are all quality indicators that can help Google understand how accurate, relevant, and authoritative that piece of content is.

But are the links themselves a ranking signal?

Outbound Links as a Ranking Factor: Our Verdict

Here’s what we know:

• The presence of outbound links, or lack thereof, on its own is not a ranking factor.
• The words in outbound link anchor text are used to help Google understand the source page’s content – just like every other word on the page. They are no more or less valuable.
• Linking to high authority sites is not an indicator of the source page’s authority because it’s just too easy to game.

Your best strategy is to use outbound links in the way Google intends them to be used – to cite sources, to improve user experience, and as endorsements of high-quality content.

Trying to use them to whisper at Google about your authority or relevance could backfire.

Overusing outbound links looks spammy in the same way overusing any other optimization looks spammy, and it could lead Google to ignore the page entirely.

Outbound links may have been a ranking signal in the early 2000s. However, Google has so many more reliable, less noisy signals to consider today.

Featured Image: Paolo Bobita/Search Engine Journal