It has been known since as far back as 2013, and suspected for much longer, that applying a redirect from 1 page to another will lose some of the original pages ranking power, link juice, whatever you want to call it – around 15% was the figure bandied about.
This applied to 301 redirects – 301 being the http status code for permanently moved, when 301ing a page, you are saying go here instead, the page has moved for good.
302 redirects, of course, never passed any juice as 302 by its very nature is a “temporary move” which means the original page will return at some point in the future.
Losing 15% of a pages ranking power could mean anything from not a lot, to losing some serious ranking positions, and that was a worry when it came to Google’s new found love for https.
The simplest, and only really effective way to switch to https (after adding an SSL certificate, of course) is to then 301 all http traffic over to https – the trouble everyone had with this was, you had 2 choices – be considered insecure by Google (remain as http) or lose 15% of your websites ranking power, on every. single. page. by adding a 301 redirect to https.
But now, things have changed.
There are new rules in town – new rules which mean any 301 redirect from http to https (presumably, only on the same domain) will not lose any link juice whatsoever, in fact, 302 won’t lose rank either even though it’s not a permanent redirect.
The latest update, and we’re a little bit cautious over it – is that 301 won’t lose any juice at all, in any circumstances, that even means 301 redirecting one domain to another, or one page to a page on another website!
So what does that mean for SEO?
Well – probably not a lot, we wouldn’t be trusting Google’s word on this, things change, a lot – and without notice too, you may see a benefit, you may not, and it may be long term, but it may quite as easily not be.
So what do I do?
In our opinions – don’t do anything different, at least for the time being. If you’re going https, then apply a 301 redirect, and of course update all links on your website to https, after all – you don’t want your website to show as insecure in the Google serps next year, do you? If you’re thinking of applying 301’s purely to benefit your SEO campaign – I’d suggest steering clear, or consulting a professional.