Google Tag Manager is a powerful tool which, among other things, helps marketing people communicate less with developers, when they need to implement an advertising pixel, conversion tracking or some Google Analytics code (which is always painful and lasts weeks or even months, if you have to work with the developers on board, who are always “busy on more important tasks”).
If you decided to start using Google Tag Manager (which is free, yoo-hoo!), have Google Analytics already installed on your site, you may face a challenge when migrating to GTM. The process may seem simple, but there is a very important thing you have to consider.
When switching to GTM, you need to remove all Google Analytics codes from your site code (GA snippet, event and ecommerce tracking, etc.) at the same time putting corresponding GTM codes to the site or corresponding settings in GTM.
No matter which trackings you already use in Google Analytics you want to be sure that after migrating you preserved all of them and didn’t leave clutter code, left from GA.
Use this checklist and your migration process will work out well.
- Check if Google Analytics snippet on your site is different from the default one (for example, your are using cross-domain tracking, user-id, etc.). If it is, when creating Google Analytics tag in Google Tag Manager, consider these settings.
- Check if you have any events set-up. To check this, go to “Top events” report. In this report you’ll see events, which triggered on your site.
- Check if you have any goals set up in all of your Views. In case some events are rare on your site, you may not see them in “Top events” report.
- Check if you have ecommerce/enhanced ecommerce setup in all of your Views. If you have, you will need to change GA codes to dataLayer.
- Check if you have custom dimensions or metrics set up (go to “Admin”, then - “Custom definitions”). If you have them setup, you will need to somehow find them in the code (that is why it is always a good thing to document all of your GA/GTM settings, so that you always know which codes you have, where and why).
- Same for custom content groupings (“Admin”, “Content grouping”).
This checklist will help you or your developer not to overlook some important settings while migrating from GA to GTM and be sure your data will continue to be gathered correctly.