You might find some interesting comments here:
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webmasterworld.com...]
Within 24 hours of the switch, our adsense plummeted by 40%.
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People are just simply not clicking as much. And even those who are clicking, Adsense is paying what some may consider a lot but not what I'm used to getting paid day in and day out.
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I checked the search engines, no declines in search engines. Google is indexing all pages quickly. Everything showing up quickly to all news feeds, etc.
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I'm sure some of you have crossed over to new sites, did redesigns, etc. (likely didnt wait 10 years like I did).
Several things to talk about. Lots of years as webmaster, seo, adsense, etc. Ok, yes, your change sure has impact:
- Your site can look the same or different
- Your site can be faster or slower
- Ads placement might be the same or different
- Your link structure can also be the same or different
Those points are usually obvious impacting your site performance as a SITE and on ADS, BUT you will have to remember, even if your site changes and looks the same, is faster, ads placed on the same places and link structure is the same, there still are things that won't be the same:
- redirects, even for keeping the url structure: it leaves a footprint
- pretty sure your html & css are not the same: it leaves a footprint
- CMS change, it sure leaves a footprint too
- Content distribution and position: it sure leaves a footprint too
Content distribution? it means how your site content goes to the bot and web browser, whatever way it looks, you can put content first (and actually you should), so, it matters too. A lot of people leave content, then navigation, then the rest (looks ok to me). After posting all of that, specially about footprints now you can understand SEs and Adsense feel that "footprint" as a major change, thus they put a whatever-color-flag on you that will last for whatever-time-they-think-it-should. There are far too many cases with clear clues on this to be solid true (oh, everyone has a voice, but dogmatic stuff invites for checking post history... personal opinions on liking or not don't add any kind of value to any kind of technical affirmation ok? just saying to keep this clear).
Sometimes things never come back to what they were. Oh BTW, I posted SEs and Adsense because they show signs of treating such changes differently, so as you said you can have the same links and traffic but the ad department still doesn't release full trust. Be patient, trace your strategy, some people will only focus on earnings but sometimes it's not the only thing that matters, mobile or not, so at times changing cms as you did sure is the right way.
Been there (OP), and some sites recovered, some didn't, took time, but as for now it's too difficult to measure because we are talking december, end of the year, traffic usually goes low depending on your niche. Me? while my sites recovered quite a bit, the hit of the thread posted here is solid, the curve behavior I say. Good luck and try to document this change as much as you can, it's very useful.