3 Case Studies Showing The Power of Canonical Tags

We’re grateful to our magnificent customer Connie Chen this week, who has shared with us 3 real-life case studies that demonstrate the power of the canonical tag.

As the Director of Search Marketing at a digital marketing agency, if you were to ask me, “what’s one small fix that would have high leverage on my website ranking?” My response would be: any fixes related to canonical tags.

I’d like to share 3 real-life examples where proper canonical tag usage has had powerful SEO results. Keep reading to learn what the issues were, how we fixed them, and what happened next.

Contents:

• A bit of background
• What’s the deal with canonical tags?
• What can go wrong with canonical tags?
• 3 real-world canonical tag case studies
• A small tag with big impact

A bit of background

First, some context.

At Moving Traffic Media, our SEO team has seen websites with a myriad of technical issues – everything ranging from duplicate content, missing XML sitemaps, and even spammy code injections that redirect users to odd places.

In most cases, addressing any of these aforementioned website issues often delivers noticeable, positive results.

More notably, however, our team has encountered several client cases where a fixed canonical tag yielded significant improvements, or an incorrect canonical tag was quietly undermining performance.

Yet, this is one technical issue that is not always the most obvious culprit in an audit.

In fact, missing and mismatched canonical tags is a growing issue plaguing websites. According to the 2024 Website Almanac, 65% of mobile and 69% of desktop pages utilize rendered canonical tags, which is up from 2022.

While canonical tag usage has increased, the percentage of mismatched canonical tags has also doubled since 2022.

Image source: https://almanac.httparchive.org/en/2024/seo#canonicalization

What’s the deal with canonical tags?

Canonical tags (rel=canonical) are HTML tags that serve as strong hints to inform search engines if a page is the preferred version of content that should be ranked and indexed (also known as the canonical page), or if the page is a duplicate.

If a page is marked as a duplicate, search engines will attribute the value of this content to the page that is marked as the original.

With self referential tags, search engines will attribute value to the page itself, while non-referential tags will point value to another page.

These tags are meant to aid deduplication and prevent indexation and crawling issues that may occur with duplicate content.

What could go wrong?

When incorrectly used, canonical tags can send confusing mixed signals to the search engine, which could then result in bad user experience, poorer site visibility, fewer keyword rankings, and stifled organic performance for an intended page.

As written in Google’s search documentation on canonicalization, “duplicate pages are crawled less frequently in order to reduce the crawling load on sites”, which could result in reduced visibility.

Here’s an example of what to avoid.

Suppose your site has a conversion page with submission forms, which we’ll refer to as the “Conversion Page.”

This is a crucial moneymaker page that should be prioritized for rankings and traffic as submission forms are the primary drivers of sales for the site.

If the canonical tag for the Conversion Page is not self-referential, this would communicate several incorrect signals to the search engine:

• The Conversion Page is not original content
• The Conversion Page is a copy or a duplicate page
• This Conversion Page is not the “priority” page that should be indexed or visible
• All ranking value and authority should be going to another page

According to Google's Search Central documentation, Google uses the canonical page as the main source to evaluate content and quality

Inconsistent signals can result in Google choosing a different page as the canonical, which could dilute the ranking strength of the intended priority page.

Allan Scott from the Google Search team says, “When it comes to trying to figure out how to weight things, one of our biggest problems is we don't know what to do when a webmaster sends us conflicting signals… If your signals conflict with each other, what's going to happen is

the system will start falling back on lesser signals.” [00:06:11:12]

This is exactly what we want to avoid. As SEOs, our job is to untangle this web of mixed signals and make sure these canonical tags are sending correct and aligned messages to search engines, allowing the right pages to gain priority in rankings and retain value.

More often than not, incorrect canonical tags are a hidden culprit that are uncovered in technical audits.

Once identified and corrected, these canonical tag fixes can not only improve traffic, but can highlight the importance of this element in technical SEO.

Here are a few real-world examples from our clients where we identified a major underlying canonical tag issue that had large impacts on perfomance.

3 real world canonical tag case studies

Case #1: canonicals pointing to outdated domain

About our client and their site:

In this first case study, our client in the real estate rental industry was struggling with poor branded and non-branded keyword rankings.

The site had difficulty ranking for rental terms in specific regions. At the time of our technical audit, the site was ranking for a minimal number of keywords:

• 154 ranking keywords total
• 24 keywords in positions #1-10
• 130 keywords in positions #11-100

The canonical tag error:

During our technical audit, we discovered that every page on the site had canonical tags pointing to an outdated domain that redirected elsewhere, instead of being self-referential.

Example of the incorrect canonical tag implementation:

In this situation, the canonical tags were sending conflicting messages to search engines.

These incorrect canonical tags limited the indexation of pages across the site and diminished keyword ranking visibility.

As a result, none of the pages on the site were receiving ranking value from its on-page content, which was reflected in the site’s organic performance.

Canonical tag fix:

After discovering that the entire site’s canonical tags were pointing to an outdated domain, we outlined our recommended fix to the client: rewriting the canonical tags to be self-referential.

By updating the canonical tag to point to the correct domain and corresponding pages, the search engine was able to attribute proper value to the overall site.

After the fix:

After the fix, we saw impressive results, with significantly improved keyword rankings:

• 724 ranking keywords total, an increase of +320%
• 65 keywords in positions #1-10, an increase of +171%
• 659 keywords in positions #11-100, an increase of +407%

Case #2: incorrect canonical tags on paginated URLs

About our client and their site:

A biopharmaceutical company specializing in gene therapy development came to us for assistance with their organic strategy, wanting to drive more traffic to their site.

The canonical tag error:

During one of our monthly reporting cycles, we noticed a large decrease in clicks and impressions to the site’s press release newsroom.

In our investigation, we discovered that during an attempted fix, canonical tags were incorrectly implemented to paginated URLs of the site’s press release newsroom.

The error resulted in losses in traffic, as seen in Google Search Console below.

Example of incorrect canonical tag implementation:

Google Search Console data:

This incorrect canonical tag implementation tells search engines that all pages in the series are duplicates of the first page of the press release newsroom, and as a result only the first page of the newsroom would receive ranking and visibility.

This would also cause indexation issues for any subsequent pages of the newsroom, making a large number of pages difficult to discover.

Canonical tag fix:

In a case like this, we recommend updating the canonical tag to be self-referential in order for content on paginated URLs to be visible and indexable.

Example of the correct canonical tag implementation for paginated URLs:

Case #3: incorrect canonical tags on blog pages

About our client and their site:

A large cryptocurrency company wanted our help with a website redesign and building their organic presence, focusing on non brand keyword rankings.

The canonical tag error:

With the help of Sitebulb during our technical audit, we uncovered over 127 orphaned pages, with more than 100 of those URLs coming from the site’s blog.

The orphan page issue stemmed from several converging technical problems, including a lack of internal links throughout the blog, Javascript-rendered content, and canonicalized paginated URLs.

Similar to the second case study above, the paginated URLs had incorrect canonical tags implemented, with tags pointing to the main blog page rather than self-referential tags.

Example of the incorrect canonical tag implementation:

Although the first page of the blog remained indexable and discoverable by search engines, the incorrect tags also caused older content on subsequent pages (page 2 and on) to become orphaned, as search engines were not able to discover the older content through any links.

Canonical tag fix:

Our recommended fix for this multifaceted issue was a three-pronged solution:

• Improve internal linking throughout the site and blog
• Add any important and priority content in the response HTML
• Update the canonicalized paginated URLs.

For the paginated URLs, each canonical tag should be updated to be self-referential in order to allow search engines to index and attribute proper value to each page.

Example corrected canonical tag implementation:

After the fix:

When the canonical tag fix was implemented, the result was a massive decrease in orphan pages, effectively reducing the issue from 127 affected pages to only 25 pages, an 80% decrease.

A small tag with big impact

Whether your client understands canonical tags or not, the results are clear: canonical tags can pack a large punch for your site’s visibility and performance.

Properly implementing canonical tags can help align all the important signals your site is sending to the search engine, preventing duplicate content issues, and strengthening your site’s ranking power.

You might also like:

• Beginner’s Guide to Technical SEO Factors
• Guide to Technical SEO for Ecommerce
• How to Find & Fix Orphan Pages