While setting up a new website, you might be tempted to use Google Tag Manager to deliver your Google Analytics tag. In this article, we will investigate the pros and cons of using GTM for Google Analytics and suggest situations when you should use it or not.
TL;DR
If you are planning to use GTM only to deliver the Google Analytics tag, you shouldn’t do it. It adds unneeded overhead to your website.
What is Google Analytics
Google Analytics is a Google online platform that allows you to track the usage of your website. It is used by millions of websites worldwide. It is most likely the richest free tracking tool available.
Google Analytics Pros
- Free
- All-in-one solution for tracking page views, events and conversions
- Richer information than just using server data
- Access to Google Demographics database (requires some configuration)
Google Analytics Cons
- You are sharing all your data with Google (might not be suitable for enterprises)
- Some data is estimated (sampled)
- It is usually blocked by ad blockers
- The interface is overwhelming for beginners
What is Google Tag Manager
Google Tag Manager is a tag management system (TMS) that allows you to manage and add “tags” to your page without changing your website code. A tag is usually a small code snippet added to a website to access some third-party feature or tool. For instance, to enable Google Analytics on your website, you need to add a tag (small code snippet) to the HTML of all the pages.
GTM Pros
- Free
- Business people (non-developers) can deploy and change tags without assistance
- Tags can be loaded based on preconfigured events
- Fallback for loading tags when scripts are not enabled
GTM Cons
- Although claimed to be accessible to marketing people, it is not ease to use for less-technical people
- Code overhead
- It is usually blocked by ad blockers
- You are sharing your traffic information with Google
Do I need Google Tag Manager to use Google Analytics?
The simple answer is no. The work to copy the GTM tag to all the pages is the same as copying the Analytics tag.
Google Tag Manager as any third-party tool, ads an overhead to your website. From the picture below, you will see that on a simple website with not much script, the GTM javascript file is the biggest of all used scripts. And if you use it only to deliver the Analytics tag, 49% of the GTM code is not used at all!
Concretely you are downloading 3 times more code than you need. And 47K bytes are unused Google code.
When would I need Google Tag Manager for Google Analytics?
In some cases, GTM might make your life easier and require less programming and you may consider that it pays off for the additional overhead. As examples we could mention:
- If you want to load only Analytics after an event and if some condition is met (e.g.: only after and if the user accept third-party cookies)
- If you work in a complex environment where the change process is to heavy.
- If you are managing a lot of tags for a lot of websites (and not only the Google Analytics tag).