For over a decade, there has been a debate among search engine optimization (SEO) experts surrounding the best practice for handling redirects—in particular, the best practice for using status codes for Google: 301 (permanent move) vs 302 (temporary move). There is a very good reason for this debate—redirects are tricky. There are HTTPS redirects (from a less secure HTTP link), page-level redirects for simple moves, site restructuring (hierarchy-based) redirects, and domain redirects. Last year, Google made it much easier for websites to worry less about page and site redirects harming their SEO value. They didn't do it out of the goodness of their hearts . . . or did they?
Why the change?
Well, I don't work for Google, so I can't give you a breakdown of all the discussions they had regarding the best way to handle redirects. Heck, I'd just love to be part of those conversations! What I do know is that Google has a high bar for web security and takes that very seriously, so much so that they started giving search rating boosts for sites loading their pages solely over HTTPS.
The problem is that those ratings boosts weren't enough to entice most webmasters to make the change. A small SEO boost over a potential 15% drop in PageRank isn't exactly going to get webmasters clamoring for the move over to HTTPS. So they started looking at how they handle page redirects and how they can make it easier for webmasters to not have to worry so much when they're handling redirects. Ultimately, Google found a less strict way to handle them, easily passing PageRank whether or not it's a 301 or a 302 redirect (temporary or permanent).
Last year, Google's own Webmaster Trends Analyst, John Mueller, stepped in to clarify any confusion surrounding the subject:
IMO SEOs fuss too much about redirects. Use the right one for the job, it's a technical thing, not a SEO thing; it's not voodoo magic.— John ☆.o(≧▽≦)o.☆ (@JohnMu) September 29, 2016
If you'd like to get into the details, he wrote a technical post about it which can be read here.
What does 301 vs 302 really mean?
I always like to think about real world examples when talking about how Google handles SEO. Let's say your favorite pizza joint tells you that they have moved to a similar location across town but they're still the same old place. What you as a customer care about most is that when you order from them, you can still order your favorite specials, and the pizza quality is equal. The location might change, but if the pizza is still the same, you'll be a happy customer. That's what Google cares about. When you move a single page or even an entire category, if your quality and user experience are the same or better, Google is happy. You'll continue controlling that page's search keywords. So, whether it's a temporary move (302) or permanent move (301), ultimately you will continue to have the same PageRank—as long as the experience for the user is the same.