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How do outbound links affect organic search rankings?

Author's avatar By Dave Chaffey 30 Nov, 2016
Essential Essential topic

Chart of the Day: New experiment on outbound links shows their impact

A lot of discussion of SEO is around the right type of backlinks, links into a site, and rightly so given their continued importance to ranking. But what about links out from a site, do they have an impact? These are discussed less often, but can have an impact as the chart from this experiment by Reboot Online shows.

The experiment involved purchasing 10 new domains which mentioned the niche term "Phylandocic". Each article mentioned 2 authoritative, related websites. On 5 of the websites, mentions are in plain text whilst on the other 5 sites, they are hyperlinked. The domains were all registered at the same time to remove any domain age influence. All domains contained 10 random but pronounceable characters and all domains were confirmed as having 0 search volume produced in Google. All sites were co-hosted to minimise any hosting related bias.

The full research gives more details, but these visual results summaries are compelling. You can see that the ranking stablised after a period of 8-10 weeks to give higher rankings for the sites with outbound links.

Outbound link experiment rankings

Here are the rankings for the term which also makes the point effectively.

Implications of the experiment?

It seems to me as I review SEO practices of different sites, that some businesses and some copywriters seem to have an attitude that all in-line links to other pages on their own site or on other sites are negative, so they don't follow this practice. Perhaps they are fearful of leaking visitors, but to me, the benefit to users of providing relevant links and the benefits of improved rankings will typically outweigh any disadvantages, particularly on a blog post. This experiment is interesting since it suggests that outbound links do have a positive impact.

In the early days of Google, whitepapers from Google research (and patents) referenced the Hilltop ranking concept related to "Expert documents". This concept hasn't been forgotten though, more recently a Moz Whiteboard Friday video asked: "Is External linking good for SEO?"

Author's avatar

By Dave Chaffey

Digital strategist Dr Dave Chaffey is co-founder and Content Director of online marketing training platform and publisher Smart Insights. 'Dr Dave' is known for his strategic, but practical, data-driven advice. He has trained and consulted with many business of all sizes in most sectors. These include large international B2B and B2C brands including 3M, BP, Barclaycard, Dell, Confused.com, HSBC, Mercedes-Benz, Microsoft, M&G Investment, Rentokil Initial, O2, Royal Canin (Mars Group) plus many smaller businesses. Dave is editor of the templates, guides and courses in our digital marketing resource library used by our Business members to plan, manage and optimize their marketing. Free members can access our free sample templates here. Dave is also keynote speaker, trainer and consultant who is author of 5 bestselling books on digital marketing including Digital Marketing Excellence and Digital Marketing: Strategy, Implementation and Practice. In 2004 he was recognised by the Chartered Institute of Marketing as one of 50 marketing ‘gurus’ worldwide who have helped shape the future of marketing. My personal site, DaveChaffey.com, lists my latest Digital marketing and E-commerce books and support materials including a digital marketing glossary. Please connect on LinkedIn to receive updates or ask me a question.

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