5 tips when troubleshooting data collection through GTM

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Troubleshooting why your data collection has stopped working doesn't have to be tedious. Check if your scenario can be helped by these steps I usually take.

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I sometimes get this question from clients who are wondering why different tools have stopped collecting data and they therefore cannot follow up on their statistics as they usually do.

Start by recreating the issue

There could be more than one reason to why your analytical tools have stopped collecting data. In order to determine if the issue is related to the tags set up through Google Tag Manager, I usually go through the following steps.

To find out where the problem lies, you want to recreate the issue yourself first. Firstly I check the previewmode in Google Tag Manager and then visit the page on the site where the tag should be firing.

If the tag is firing

  1. If the tag fires, login to the tool (if you have access to the third party tool connected to the tag) to see if you can see any data being collected, or if/when it's stopped.

    In Google Analytics you can check in real-time, to see that a GTM-tag is both fired and is sending over data. If the tag is fired but no data comes through to GA, there's something wrong with the connection here. The tag might be sending data through to the wrong UA-ID for example or the tag/script for the UA-ID itself isn't triggering.

    If the issue is that there's a specific goal in Google Analytics is no longer collecting data, check the setup in Google Analytics. The event might still be triggering, but the setup of the goal itself might be depending on other factors such as destination page etc.

  2. If everything looks ok in Google Tag Manager, no change has occurred related to the tag itself, check the ID in the script (if it's a tag connected to an ID like for example Facebook pixel). It might be that the third party tool has updated either their script or the ID in the scipt connected to the account where the data should get collected.

If the tag isn't firing

  1. If the tag doesn't trigger on the other hand, check in the preview box Firing Triggers to find out which condition is hindering the tag. It could be that the URL of the page has changed for example, a class name might have changed or it could be that the tag has been set to fire after another specific tag, which in turn isn't firing.

  2. If there's a tag which is set to trigger before other tags and there's a problem with this one, that might be hindering your tag from getting fired. This could be the case with for example cookie banner related tags.

    In a situation where a tag is depending on another one to trigger first, don't be too hasty to change the settings for your tag. You might want to focus on making the other one trigger as planned.
    Your tag might contain for example a cookie setting which the user first has to accept (an acceptance you might get only by making that first tag trigger).

  3. If your tag is connected to Google Analytics, start by checking the event and try to establish when it stopped working. Thereafter cross reference that date with versions in Google Tag Manager, to see if there's anything that's changed that could have caused the tag from stopped firing. Also check if the tag itself has changed or not.

To sum up

Recreate the issue and determine if the tag is firing or not.

If the tag is firing

  1. Login to the connected tool and check the settings
  2. Check the version history and settings for the tag in GTM and compare to the original script

If the tag isn't firing

  1. In preview mode for the site, check if there's a condition which isn't fulfilled for the tag
  2. Check if there's another tag which is preventing your tag from being fired
  3. Compare dates for the third party tool against versions in GTM to see if any changes have been made that could have affected your tag

There will of course be other scenarios than these but I usually find when having gone through the above that I find the underlying issue.

Hope this has helped some of you getting your tags sorted.

Happy analysing everyone!