i am not planning to recover anything at all. problem is that i have old wp site with old theme and i want to replace it with another theme. in order to make it visually good looking and also functional without loosing ranking..

so you are telling me to change theme and then keep eyes on Analytics. In case of some changes recover old one (old theme)... am i right?
what else can you advice?? are there any kind of guidelines for theme changing?

Yes, it does matter because they can be very different the way they're coded and how they layout their pages. For people who don't know much about on-site SEO or how themes are coded, it can change their entire site structure without them knowing.

Of course it does. If you change all the HTML markup of the site, why would that not affect SEO? Theme is the piece that brings everything that is not content.

It's possible that the change is minimal, or that the site will be at permanently higher level than before. It's also possible that the site will drop like a stone, and remain at this lower level. There's probably a period of "Google dance" when the SERP results vary drastically within a short period of time. The first drop is usually not the verdict.

You kind of referred to the possibility that bounce rate increases ie. that users don't like the new site for one reason or another. That's a very good point.


And how would you test a bounce rate or traffic? A/B testing might give you data on bounces if your tool collects data on users that leave instantly, but there's no way to see if traffic drops.

If you're "just testing this new template on a live site for a bit" and leaving it on for couple of weeks to see the verdict, and then going back to the original, from Google's perspective you're essentially redesigning your site twice in a row. That's definitely something I would not suggest.

You should keep your eyes on statistics, but Analytics isn't a tool that you can use in this way.

in terms of popularity as i know genesis and thesis are top brand rather than personal press. So fron your point of view both of them gonna work fine

Take the obvious precautions. Don't test new themes on your live site, but clone it and see that everything works before installing the theme. See that the URLs stay the same (Why would they not? Well, I've seen all kinds of silly stuff in this space...). See that H1 tags and titles exist and are the same. Try to check that the new theme doesn't do anything too weird with the content. See that the link structure makes sense, and there aren't a ton of unnecessary stuff around. If you're using one of the SEO plugins, keep using that same plugin at least for time being.

If you can afford or stomach it, change things gradually. Most people need to do sites as a project or are too impatient to do it slowly.

The themes you mentioned are indeed good ones. I personally don't like Thesis, but it's known to work. Genesis was my theme of choice some time ago.