Calculating The True SEO Costs Of Major Site Changes

Over the past year we have worked with a number of organizations that have chosen to relocate their sites from an existing domain to a new domain. One of the questions that always comes up early in the process is “how much traffic are we going to lose?” It is an excellent question and not an easy one to answer, but in today’s column I am going to explore that exact question.

Here are some of the types of changes that can have an impact on traffic or rankings.

Domain change. Any change in the domain, such as a move from to The most common reason for doing this is a branding change of some sort. An existing business may be changing its branding, or one business entity may have been acquired by another one and the two sites are being merged.

Structural changes or URL changes. These are changes where the content that lives on a given URL on (such as about-us.html) gets moved to a different URL (such as about-us.php). URL changes can be “wholesale” (change nearly all or all of them), “heavy” (change a lot of them), “moderate” (change some of them), “light” (change only a few), or not done as all if you simply copy the exact site structure from one domain to another.

Structural changes often happen as a result of a change in the technology used to implement a site. For example, a business may have been using Cold Fusion as a content management system, and then switches to using ASP. The other major reason for structural changes is when wholesale content changes are made.

Content changes. Changes to the content on pages can happen without changing the URL structure of the site, by simply rewriting content on the pages, or something that causes structural changes to the site. As with URL changes, these can also be heavy, moderate, light, or not done at all.

Content changes may be made for many reasons. Perhaps the target audience has changed. Perhaps the basic positioning of the organization has changed. Another possible reason is to revamp the content as part of a wholesale expansion of the site.

Each of these things can happen independently. You can make content changes without changing the domain or the URLs. You can change the URLs without changing the domain or the content.

What are the true consequences?

You are going to lose traffic. That is a fact. Even if you only perform a domain change and preserve the exact same site structure and content, you will lose some traffic. In this simplest of scenarios you can minimize the amount of traffic loss by using 301 redirects from each URL on the old domain to point to the same URLs on the new domain, alerting the search engines that the new URLs are the important ones.

In principle, this simple domain change scenario sounds like one where there should be very little lost traffic. One factor to consider though is that of “trust.” Any time there is a domain change it may be reflective of an ownership change, even if the WhoIs info is not updated. For the search engines this raises the possibility that the new owner isn’t as trustworthy as the original owner.

Another factor concerns the 301 redirects themselves. In tests we have done at Stone Temple Consulting, we have seen evidence that they pass through the majority, but not all, of the link juice to the destination page. Sometimes there is a delay between the implementation of the redirect and when the search engines pass through the link juice, which can result in a significant drop in search engine traffic. In the medium to long term a simple domain change is usually not that costly (though there are exceptions). You may lose 20% to 40% of your traffic in the short term, and 10% to 20% in the medium to long term.

As you might imagine, the more complex the changes, the greater the potential negative consequences. For example, combining a domain change with URL changes will definitely be more costly. You have given the search engine more reasons to trust the site less, and your 301 redirect map just got more complicated. Assuming you completely restructure the site so all the URLs change, you can expect to see traffic loss of about 30% to 50% traffic loss in the near term, with gradual improvement on that over the longer term.

In our final scenario, if you change your domain, URL structure, and your content, you are asking for trouble. The big reason for the cost here is that the new content you create is not the content that people saw when they linked to your site in the past, even if it basically about the same subject matter. This probably results in the search engine significantly discounting the value of those links. Traffic loss in this scenario is likely to be 50% or more in both the short and long term.

To summarize:

Type of Change Short Term Medium Term Long Term
Domain Change Only 20% to 40% 10% to 20% 10% to 20%
Domain and Structural Changes 30% to 50% Improves over time Improves over time
Domain, Structural, and Content Changes 50% or more 50% or more Might improve over time

Disclaimer! These numbers aren’t exact, and your mileage will vary. The actual impact of changes to your site will depend on many factors that are not possible to cover here. In addition, the chart assumes that you don’t do a lot of incremental link building to bolster rankings. However, savvy site owners rarely stand completely still.

How to mitigate the damage

Once you have made your changes, and assuming you have followed Google’s recommended best practices for doing so, the main damage control you can do is get new links to the site. In particular, if you can continue to get links at a pace similar to, or better than, what was happening before the move, this is a strong positive signal to the search engines that all is well.

Also make sure that you ask people who have linked to you in the past to update their links to go direct to the new site, bypass those pages where you’ve put 301 redirects in place. If a significant percentage of your past linkers do this it is also a very strong signal to the search engines that your site is still trustworthy in its new location.

The best remedy? Stop and think about the consequences of a move before committing. There will be a cost, and your business plan probably does not call for a dip in traffic to, and orders from, the web site.

The bottom line: Don’t make major changes to your site unless you really have to, and are willing to pay the price.

Opinions expressed in the article are those of the guest author and not necessarily Search Engine Land.

Related Topics: Channel: SEO | Industrial Strength | SEO: Redirects & Moving Sites


About The Author: is the president of Stone Temple Consulting, an SEO consultancy outside of Boston. Eric publishes a highly respected interview series and can be followed on Twitter at @stonetemple.

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  • LinkLift

    Eric, this seems a bit too optimistic. From our experience, the losses for simultaneous domain and structural changes are higher, even if you do a decent job 301ing whatever you can.

    Also, from experience I would say the effect of the 301 seems to wear off over time (or the dampening factor increases), so it is indeed a good idea to follow up with some of your link sources and inform these fellas about the new URL of the content.


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