Is there a correlation between social shares and inbound links? The question goes to the heart of why people share content and why they link to content.

If people share and link to content for similar reasons then logically you would expect a very strong correlation between shares and links. However, if people share and link for different reasons you would expect to see variations in the correlation for different types of content.

Why does this matter? Understanding why people share and link to content is eessential for both content marketers and SEO teams. Ideally we want to create content that is amplified through both shares and links. My analysis of 10,000 posts suggests that some forms of content are very unlikely to acquire both shares and links.

Key Insights

Our review of 10,000 posts found a positive correlation between links and shares at an aggregate level, suggesting there are similar reasons for sharing and linking, however:

the relationship between shares and links varied significantly depending upon the content type and format

shares happened much faster than links and appear important in gaining attention and traction for content

there was a very weak relationship between shares and links for content such as quizzes

content published on specific sites such as LinkedIn and BuzzFeed got very few links relative to shares

there was a particularly strong correlation in the area of B2B content marketing where content has intrinsic evergreen value

The analysis suggests at an overall level the reasons for sharing and linking to content are similar. However, the lower correlations and lower ratio of links for content such as quizzes and for list posts published on sites such as BuzzFeed suggest there are differences. There appear to be some forms of content that people are willing to share but which are less likely to acquire links. The analysis suggests that content such as B2B evergreen content is more likely to acquire links as well as shares, which is reflected in a high correlation of shares and links.

Thus if you want to create content that gets both shares and links the analysis suggests you should avoid content such as quizzes and simple list posts and focus on longer evergreen content that has more intrinsic value.

I would stress that this is an hypothesis which I am putting forward as the basis for further discussion, debate and research. My data set for this initial research was quite small at 10,000 posts and more extensive research exercise needs to be undertaken with larger data sets with agreed definitions of backlinks and social shares, clearly defined categories of content and data on the acquisition of shares and links over time. Full details on the data I used and my approach is set out at the end of this post.

There Is A Positive Correlation Between Shares and Links

Previous studies have suggested there is a positive correlation between shares and links, such as this analysis published on Moz.

My random sample of 10,000 posts found an overall positive correlation of 0.62 which indicates a fairly strong correlation between shares and links. This was slightly greater than the previous studies have found though I should say again that the data set I used was relatively small. However, it does suggest there are similar reasons for sharing and linking to content at an aggregate level.

However…

When I created sub-sets of data I found quite significant variations.

For data sets of articles on news sites such as the New York Times, The Guardian and Huffington Post I found stronger correlations of up to 0.8. The correlation increased even further when I created sub-sets of data of articles from B2B sites to almost 0.9.

By contrast when I created data sets for content published on sites such as LinkedIn and BuzzFeed there was a much weaker correlation (as low as 0.3) and a very low number of links to shares. I also found low correlations when I created data sets for specific content types such as quizzes.