Is it worth switching from underscores to hyphens in the URL?

[MarloSchneider]

I work for a website that recently did a redesign, and switched from hyphens to underscores. We have seen some drop in traffic, although that may be attributed to the migration.

I have read that while Google prefers hyphens, the underscore problem is not as much of an issue as it used to be.

Is it worth 301'ing the page to a version of itself with hyphens instead of underscores in the URL?

[irvingw]

You said it used to be hyphens and then was changed to underscores. if this was done recently then change it back and don't bother 301'ing unless you got a decent amount of links in that time period. i am assuming you 301'd the hyphens to the underscores, if so you need to undo that was well.

[danatanseo]

Hyphens vs underscores doesn't make a difference any more. If you're purely thinking of making the change for SEO purposes, I wouldn't do it. I agree that the drop in traffic you are seeing has more to do with replatforming and rewriting all of your URLs. This is pretty normal. Hope that helps!

[MarloSchneider]

Sorry, let me clarify. By used to I mean before the domain was migrated over. So it was hyphens on the old site, but was changed to underscores on the new site.

[Whitespark]

The drop in traffic isn't because Google prefers hyphens, it's because all your page URLs changed. You had a bunch of web pages that Google knew about, were in its index, and now they're gone. You now have a  bunch of new pages that have to start building trust and authority from scratch.

I'd change them back to dashes, then set up 301 redirects for all the underscore versions.

[danatanseo]

Darren is absolutely right. However, it seems unclear as to whether or not you set up 301-redirects from your old URLs to your new URLs. If you did, then the drop should only be temporary as Google figures out where the new URLs are and the old authority is passed to the new pages (or at least most of it). If you didn't do any 301-redirects, and you still have access to a spreadsheet or sitemap of your old URLs I'd encourage you to set up 301 redirects as soon as possible. Otherwise, it will indeed be like starting completely over with a new site, regardless of hyphens or underscores.