Linkody Link Rot Study & Link Building Statistics

Link Rot Case Study Featured Image

Backlinking has been a fundamental SEO strategy since the start. However, links are subject to a common issue known as “link rot”. When links die, your website loses all the overall link value these links were providing.

Our data shows some interesting statistics. About 8.03% of all links break within the first 3 months, and a significant 44% of links are gone after 7 years. That’s almost half of your website’s backlinks!

Moreover, our research reveals that the most frequent reason for link loss is the removal of links from content, accounting for 50.2% of cases.

In this article, we’ll dive into the details of link rot. We’ll explain what it is, why it occurs, and most importantly, how to protect your website from its impact.

Methodology

The Problem

We started by recognizing a common challenge in decision-making – estimating how long it takes for specific events to occur. In business, it might be the time it takes for a user to subscribe or generate revenue. In the context of SEO, it could be the time for a newly published article to get indexed.

So, we asked ourselves: how long does it take for backlinks to deteriorate or ‘rot’?

Our approach involved using data from our own backlink tracking tool, Linkody. This tool checks millions of links individually every 24 hours, giving us precise insights into when and why links stop working.

However, we faced a unique challenge. Some of the data was ‘right censored,’ meaning that some links had already rotten while others hadn’t. We couldn’t wait indefinitely for data to come in, so we needed to finalize our analysis and make observations to determine when links typically rot, even if some hadn’t yet reached that point.

The Solution

Here’s where the Kaplan Meier function comes in handy. It’s a tool that calculates the likelihood of something, in our case, a backlink, surviving for a certain period.

Survival analysis can be quite powerful. That’s why we chose to use the Kaplan Meier method to estimate when backlinks tend to stop working.

This method provides a visual representation of the survival function. It was developed by Edward Kaplan and Paul Meier in the 1950s, named after them. What’s great about this function is that it doesn’t assume anything about how the data is distributed. It works with censored data, even when some values are missing, by comparing it to time.

In simpler terms, we used this method and our massive database of millions of links to create graphs that show when a backlink is likely to die after it’s acquired.

Link Rot Case Study Results

Now that we’ve explained the method and the reasons for our analysis, let’s see what the numbers reveal about losing backlinks.

All Lost Links Statistics & Data

The graph below displays the likelihood of links surviving over time. This includes all types of links from various websites, regardless of their Domain Authority (DA) status.

Link Survival Rate

Let’s have a look at these numbers for a few periods of time:

  • The survival rate after 1 month is 96.61%, meaning 3.39% of links will rot during that period
  • After 3 months, the survival rate drops to 91.97%, meaning 8.03% of links will rot during that period
  • After 1 year, we’re down to 82.36%, meaning 17.37% of links will rot during that period
  • After 3 years, the survival rate is 71.6%, meaning 28.4% of links will rot during that period
  • Finally, after 7 years, only 56.61% of links survive, meaning 43.39% of links will rot during that period

Takeaway

Backlinks decay consistently, regardless of a website’s size and authority. While the rate of link loss slows down in the first year, it stabilizes afterward, and stays surprisingly rapid. In just 7 years, nearly 50% of all links are lost.

This is huge!

Do-Follow vs No-Follow Backlinks Rot Comparison

Do-follow and no-follow links don’t hold equal SEO value. Do-follow links are the ones that pass on link ‘juice’. Typically, link builders prioritize these types of links.

We wondered if do-follow links deteriorate at a different rate compared to no-follow links. We used the same approach for both types and plotted the results on a single graph for easy comparison.

The findings might be eye-opening.

Here’s a graph illustrating the survival rates for do-follow links (blue) and no-follow links (red).

Do-Follow vs No-Follow Survival Rate

Observe how the curve for do-follow links remains steady while the curve for no-follow links sharply declines in the first year. After this initial period, both types of links deteriorate at the same pace.

However, due to the rapid decline in the first year, no-follow links consistently maintain a survival rate 16% to 18% lower than that of do-follow links.

Takeaway

The do-follow vs. no-follow link comparison shows that do-follow links deteriorate more slowly than no-follow links. This leads us to the conclusion that do-follow links should be a crucial requirement in link exchanges and general link building.

Not only do no-follow links lack SEO value, but they also decay faster than do-follow links. This means that even the referral traffic generated by no-follow links will diminish more rapidly than that from do-follow links.

How Does Referring Sites’ Authority Affect Link Rot Speed?

Domain Authority (DA) is a metric on a scale of 0-100 calculated by Moz. Through our partnership with Moz, we are able to provide this DA metric for each link that our tool monitors.

In this section, we’ll be focusing on do-follow links only. We ran the same analysis for referring domains with a DA below 26, between 26 and 50, between 51 and 75, and above 75; and for 3 periods of time: 1 year, 2 years, and 3 years.

Let’s take a look at the difference in survival rates between referring domains of various domain authorities.

Referring Sites DA

Unsurprisingly, high domain authority backlinks rot slower than backlinks from lower authority referring domains. The differences are very consistent for the 3 time periods examined in this study. We can see that a higher referring domain authority leads to higher chances of survival.

Our assumption is that higher referring domain authority sites have been around for longer and have less of a chance to disappear or possibly reorganize their content in a way that would break their links.

Takeaway

Many factors play a role when it comes to a backlink’s overall value. One of the most important factors is the referring domain authority. The higher the authority of the referring domain, the more link “juice” is passed onto the target domain.

That said, we have now discovered that these links are even more valuable since they rot slower. This is definitely something to take into consideration when conducting different types of link building strategies.

Link Survival Rate Per Industry

Next, we decided to delve deeper into the data and see how each industry fares regarding link survival.

The following graph shows the survival rates of do-follow links for various industries and niches.

Links Survival Rate per Industry

As our graph shows, adult and reference industries and niches have the lowest survival rates. Moreover, their loss rates are identical for the first 230 days.

The health industry has the best survival rates, 82.29% of links survive after the first year and 72.79% after 2 years. To compare with a few of the other industries:

  • 72.59% of links leading to business sites survive after 1 year
  • 77.69% of links leading to art sites survive after 1 year
  • 81.23% of links leading to games sites survive after 1 year
  • 81.58% of links leading to sports sites survive after 1 year

Takeaway

Judging by our data, the adult industry has the highest rot speed among the rest. This is likely because it is a very competitive niche with fewer resources available. These sites are also highly likely to employ black hat SEO tactics as well.

What surprised us the most was the reference industry (dictionaries, education, maps, museums, etc.). Namely, this industry has slightly better rot speed than the adult industry but is not far behind. With similar survival rates, we wonder if these sites are getting spammed a lot, resulting in constant link removals.

Health, sports, games, and recreation industries are among those with the lowest rot rates, with society, business, and computer industries being in between.

Comparing Backlink Rot For Low & High Authority Websites

Finally, we were curious to know if domains with higher authority tend to lose their links at a slower pace than domains with lower authority.

For this part of our analysis, we split our dataset between domains with an authority below or equal to 45 and the ones with an authority above 45.

The following graph shows the survival chances for do-follow links leading to low authority domains (blue) and high authority domains (red).

Low DA vs High DA Backlinks Survival Rate

By using the Kaplan Meier analysis, we found out that websites with a higher Domain Authority are more likely to lose fewer links than websites with a lower Domain Authority. Moreover, the difference increases over time, and the gap between the two keeps getting bigger.

Websites with a DA of over 45 lost only 11% of all links leading to their pages. On the other hand, websites with a DA of less than 45 lost 16% of all links leading to their pages in the first year alone.

  • 15.88% of links leading to sites with low DA are lost in the first year
  • 10.89% of links leading to sites with high DA are lost in the first year
  • 23.42% of links leading to sites with low DA are lost after two years
  • 15.59% of links leading to sites with high DA are lost after two years

You may wonder why this happens. There are many variables, therefore we can only assume that websites attract backlinks from domains that have similar domain authority. As we’ve mentioned in our previous section, the higher the authority of the referring site, the higher the chances of link survival.

Why Are Links Lost?

As our link building statistics show, there’s a clear tendency for sites to lose backlinks after a specific time period of acquiring those backlinks.

There are three major reasons why this happens:

  1. Links are removed
  2. Website is down or not responding (cannot scrape)
  3. HTTP error
Why Are Links Lost

50.9% of links are removed

Link not found is the most common reason for link loss, with half of all links most likely being removed by someone.

31.8% are from sites we cannot scrape

The second most common reason for link loss is that we cannot crawl the content due to the site experiencing technical issues, the server is giving a timeout, or the website just does not exist anymore.

These cases amount to almost a third of all site backlinks.

17.3% are from HTTP errors

HTTP errors are the least common reason, with either the page missing, or the server cannot serve the content at the time of the crawl.

These HTTP errors can be broken down into three main types:

  1. 404 and 410 errors
  2. 5xx errors
  3. other
HTTP Error Types

59.4% are from pages that are not found (HTTP 404 and 410)

When this happens, it means that the referring page has been deleted, content has been misplaced, or the slug has been changed without a redirect in place toward the new page.

22.3% are from server errors (HTTP 5xx)

This means that the server cannot serve the content and therefore we cannot check if the link is still there.

Takeaway

There isn’t much we can do if a website doesn’t exist anymore or the server doesn’t deliver the content due to technical reasons. What we can do is take note of the backlinks and conduct link reclaiming activities.

That said, in about 50% of these cases the links have been removed, which can be quite frustrating. If it’s a link that you’ve acquired or negotiated for via link building, you can easily reclaim it.

Regarding the loss of backlinks due to HTTP errors, almost two-thirds are from 404 and 410 errors, which means the content has been deleted. These types of links represent 18.59% of the total links that rot.

Although these are harder to reclaim, it’s still possible to ask the referring site to place those links on different pages.

You’re wondering how you may do that? We have the answers in the next section.

Link Reclamation – What it is & How to Regain Lost links

Analyzing our findings, we’ve just seen that over time backlinks break and rot, causing your site to lose significant value in the process.

While link building may not be easy, once you start doing it you’ll see what kind of value it brings to your site. When you notice that some of those hard-earned backlinks are now lost, it can be quite frustrating.

This is where reclaiming links comes in, and why it should be an integral part of your strategy.

Let’s start with the definition. 

What is Link Reclamation?

Link reclaiming is the process of identifying removed or broken links that lead to your site and replacing or fixing them with updated URLs. It’s not as alluring as link building, but it’s crucial if you wish to preserve a solid backlink structure for your site.

How to Reclaim Lost Links

Reclaiming lost links isn’t difficult to do, but you’ll need a process in place before you even start doing it. First, you’ll need to know which of your links have died.

To do so, you can use various tools, such as Ahrefs or our very own backlink tracking tool, Linkody, which allows you to track every single link leading to your site. This way, you can know exactly which link rots and what the cause is.

Our tool is easy to use and understand. It has a simple interface and lots of functions/options for you to keep track of your link building campaigns. Additionally, you can use this tool to keep track of all types of backlinks, including the ones you acquire in a manual way, i.e. link exchange and outreach activities.

Next, you need to contact the sites’ owners and reach out to them to see if they can update and fix the link that leads to your site.

However, do note that you may encounter negative responses, so you’ll need a backup strategy in case this happens. We recommend conducting research on the lost backlink and the type of website and finding other suitable sites that may be willing to link back to your site instead. This way, you will be able to reclaim the lost link, even if you didn’t do so with the original site in the first place.

Lost Link Building Statistics Summary

Links are bound to rot at some point in their existence as the web is constantly changing and evolving. Our analysis and case study provides truth to this statement, as our numbers above have shown.

However, it’s not all doom and gloom. You can keep track of your backlinks and backlink profile structure to avoid huge losses by acting promptly and compensating for the lost links with the addition of new ones.

After all, SEO is not a do-it-once and leave it hanging type of a deal. Especially since link building is one of the most important factors if you wish to see huge success with your website.

For this reason we created our tool and conducted such an extensive link rot case study. Hopefully, this article will assist you in your link building endeavors.

Infographic - Link Rot Case Study