Implementing hreflang can be a challenging task for many SEOs. The countless syntax variations across several languages can be difficult for those with little understanding of more than one language.
There’s also the added complexity of understanding specific language nuances and regional targeting which would only typically be understood by a native speaker or someone who had thoroughly studied the language.
Incorrect hreflang implementation can cause many complications (i.e., duplicate content, erroneous indexing and poor SERP visibility) detrimental to SEO performance.
It’s imperative to implement hreflang with care. Thankfully, hreflang is well-documented and related issues can be identified through various SEO tools.
Hreflang errors study
To determine how widespread hreflang issues are and which ones are more common, I partnered with NerdyData, which gave me access to their database of websites that contain hreflang code.
NerdyData provided a list of 18,786 websites that contain at least one instance of hreflang declaring an alternate within the source code. Thus, this study only accounts for hreflang implemented in the <head>, not through XML sitemaps or the HTTP header.
I carried out the study by:
- Running crawls in Screaming Frog to validate the presence of hreflang on the homepages.
- Removing GEO-IP redirects so the complete list of URLs resolves in 200s.
- Utilizing HreflangChecker.com and Visual SEO Studio to process the URLs in batches to identify common issues identified by the tools.
31.02% of websites contain conflicting hreflang directives
My findings show 31.02% of websites serving multiple languages have conflicting hreflang directives. Conflicting hreflang can happen when a webpage has various hreflang tags for different languages and geographical targeting.
Put simply, more than one URL has been assigned to an individual language or region, sending confusing signals to search engines. For example: