There was a mild stir on SEO Roundtable recently when the ever-vigilant Barry Schwartz reported this tweet from Google’s Gary Illyes:

Gary Illyes 3xx Redirects Tweet

The key headline is that, apparently, any type of redirect (301, 302, 307, etc) will not lose PageRank value anywhere along the chain. This is directly at odds with the usual SEO doctrine of

  • 301s pass authority (but not in a “leak proof” sort of manner – theories on “how much authority is passed” by a 301 range from 99-95% downwards depending who you ask)
  • 302s don’t pass any authority
  • Nothing else passes any authority either (307s, 300s, 303s etc – any other 3xx code)

Now we’ll put aside the fact that Gary Illyes has mentioned the term PageRank which seems charmingly antiquated these days (certainly since Google retired PageRank as a publicly available measurement by dropping it from toolbars etc) I’m afraid I have to put my sceptic hat on here and say I don’t buy it. Not for one moment.

If Google is saying that 301s are now “watertight” in terms of passing PageRank/offsite equity/authority (or whatever you want to call it) then…well, I can just about get behind this. With a robust redirection plan, and ensuring that onpage SEO and content is as sound or better than its previous incarnation, it is now perfectly possible to relaunch a website with as close to zero traffic loss as makes little difference. Not anywhere near guaranteed, but certainly possible.

The idea that 302s, 307s and other 3xx redirects of the varied family work identically to 301s for preserving PageRank and maintaining visibility, however, is one I absolutely don’t agree with. It may sound idiotic to some people to decry against Google but anyone who has worked in SEO for any length of time is more than familiar with the search giant’s tendency to say something which in day to day reality just isn’t reflected in how the natural algorithm works.

This is partially due to the fact that parts of Google’s algorithm write itself these days – things like RankBrain, for example – but also I think just that the darn thing is so huge and complicated that it must be hard even for the engineers at the Big G itself to keep track of all the various bits and how they interact.

However there’s more direct and clear evidence for why I don’t believe that 302s (etc) are valid as redirect types for the vast majority of websites. Aside from the fact that the various 3xx redirects exist for a reason and should be accordingly used in appropriate situations (for example, if a URL move is permanent it should be a 301 redirect because that’s what the damned thing exists for), redirecting URLs with 302s or other inappropriate 3xx redirects is a great way to kill visibility.

Here, I’ll show you a graph. Picture for a thousand words, and all that.

302 Redirection Rank Graph

This graphs the daily sampled rank for a high priority keyword for a retailer with a particular URL ranking very well. Note the jiggling in position (between about sampled rank 1-5) as we enter peak season – a nice example how how volatile the SERPs become during those peak traffic and interest seasons as everyone jostles for position – and then the sudden spike.

With no onpage changes and nothing else altered, how in the world did this lovely ranking URL drop from the top 3 to comfortably beyond page two on Google?

It was redirected to a new location. With a 302.

See where the rank shoots back up to the top of page 1?

The 302 was changed to a 301 redirect, and almost instantly the visibility recovered.

This, ladies and gentlemen, is why you should always make proper use of your 3xx redirects to achieve what you need them to – for users, and for SEO. Don’t take what anyone – even a Googler – says at face value unless it can be backed up. Test before you roll out on a big scale. Assume nothing.

The folks over at Moz explain all this rather more eloquently in their recent post, but the key points are

  • Use 301s if you’re moving or migrating your website or any URLs.
  • Only use 302s if you really are moving something temporarily – “temporarily” is a timescale that can vary, but generally I’d say anything less than 5-6 weeks can be temporary. Longer than that and you might as well call it permanent in the fast-paced digital world.
  • Use other 3xx redirects only when strictly needed and definitively appropriate as response codes. Wikipedia has a nice list.
  • Remember Google isn’t the only search engine in the world either – so following best practice and not just hoping that “Google will get it” isn’t a very good idea in any case!

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