Why are desktop rankings going up & down but not mobile

[OldFaces]

I'm monitoring SERPS (primarily via Search Console, but have subscriptions with other services) and have noticed that our SERPs have been going down in desktop but remain constant with mobile and tablet.

Besides the "SSL" ranking perk (our site is not yet 100% SSL) what else could be causing such drastic ranking differences in SERPS for desktop only? Again mobile and tablet remain constant.Yes we do have a responsive design.

Any thoughts?

[Peter_S]

Since Google one said the mobile index became the primary index, may be they use the desktop specific index to do all kind of testing and experimentation, while the mobile index remains more stable.

This is also possible that the SERPS served to desktop users is again more personalized than the mobile SERPS. I assume that it might be easier for Google to collect information about a desktop user, than mobile one. Therefor being able to personalize more the results. Just a guess.

[OldFaces]

Good guesses! I appreciate your approach Peter.

[dipper]

desktop is the primary result set still, therefore mobile is based on the desktop results (in many ways), so you've got to get the desktop results right and stable, before pushing out to mobile result set.

[keyplyr]

Hi OldFaces - Desktop and Mobile are different indexes, with some different ranking factors. Desktop searches are going down proportionally as the web moves more & more toward mobile.