I have Google Analytics installed, and I would like to install Google Tag Manager. How do I install GTM and not lose my GA data? I know that normally GA is installed after GTM. Is there a way to add GTM to GA? I think I am using the UA version. Or do I need to uninstall Google Analytics and start all over with GTM?
You definitely don't need to "uninstall" GA if you plan in migrating over to GTM. A possible strategy you might consider is to:
- include the GTM snippet on all your pages - this has no negative affect on GA at all. You're just putting the GTM code on your site without any tags yet.
- In GA, create an additional property for you to send TEST data into. You'll need this later on when you create your GTM tags.
- In GTM, create a page view tag that sends data to the TEST property. You should also tag your events and anything else you are already tracking with GA, because you basically want to replicate all your GA tracking but with GTM (and send all that into the TEST property).
- Allow this tag to collect data CONCURRENTLY with the normal GA tracking. You'll be able to see if GTM is correctly placed on all pages, as the pageview data and all other data should be about the same. At this point, you still are not impacting your GA tracking.
- Once you are satisfied that GTM has collected valid and accurate data, you can then consider removing the on-page GA code.
In this way, there is no data loss at all and you should be able to easily transition into GTM.
Note that the steps above are rough (and possibly incomplete), but the major steps are there, and you should make sure you do thorough testing!