Last Updated: May 20, 2022

Table of contents for creating your own Google Analytics Tag auditing system

1. What is Tag Auditing?
2. Why do we need Tag Auditing?
3. Tag Auditing Tools
4. Google Tag Assistant
5. Ghostery
6. Tag Inspector
7. Manual Tag Auditing
8. Website Scraper Tools
9. Custom Google Analytics Tag Auditing System
10. Classic Google Analytics Tags
11. Universal Analytics Tags
12. Other Marketing Tags

What is Tag Auditing?

Tag auditing is the process of scanning tags on your website to ensure that you are collecting data accurately.

By conducting tag auditing, we are just making sure that all the data collecting tools, like Google Analytics, Google Tag Manager, Facebook and any third party tools, are tracking codes implemented on your website are working properly without any issues. Tag auditing is a first step to ensure that we are collecting the right data.

You can perform a tag audit manually or by using tag auditing tools. It is only easy to do manual audits if you have very few pages on your website. However, for medium or large size websites, it is not possible to do manual audits. In such cases, you need to consider using one of the tag auditing tools which are available on the market.

These systems should be able to crawl your website and look for those tags which are broken and also inform you of the tags which are working correctly. This process needs to be carried out in regular intervals to make sure that the data you collect from your website is accurate, which is key to making important business decisions.

Why Do We Need Tag Auditing?

The main goal of tag auditing is to identify points of failure (broken tags) on your website and make sure that they are fixed on time. This in turn ensures we are collecting accurate data in our analytics system.

Below are some of the key points that we should be covering as part of our tag auditing plan:

1. Does every page on the website have Google Analytics tracking code implemented?
2. Does every page have the correct analytics tracking code?
3. Do we have multiple property IDs implemented on our website?
4. Are there any tags that are firing multiple times on the website?
5. Are we using the right accounts to link Google Analytics to other tools?

Tag auditing is used to identify various tags (tag is a piece of JavaScript code) on a website for the purpose of:

• Upgrading from Classic Google Analytics to Universal Analytics
• Migrating Classic / Universal Analytics tags & configurations to Google Tag Manager
• Debugging various Google Analytics tracking code issues
• Identifying and removing tags that no longer serve the purpose and should be removed in order to clean the website code.
• Migrating non-Google tags (like Facebook tags, Omniture tags) to Google Tag Manager.

In tag auditing, we identify all the tags currently being deployed on a website. It doesn’t matter whether these tags fire or not. They need to be identified and then updated, migrated or removed.

There are three methods through which you can identify various tags on a website:

1. Tag auditing tools
2. Manually
3. Website scraper tools

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Tag Auditing Tools

There are various free and paid tag auditing tools available in the market. The ones which I frequently use are:

1. Google Tag Assistant
2. Ghostery
3. Tag Inspector

Google Tag Assistant

Google Tag Assistant is a Chrome extension through which you can identify and validate the implementation of various Google Tags fired on a web page.

Once the extension is added, make sure that it is enabled. If the extension is in a disabled state, first enable it and reload the page. Once you have reloaded the URL after enabling the extension, you will see all the tags found on the page. 

In the extension, you can see different colors next to the tag type. Every color in the tag assistant indicates a different meaning of the tag performance. 

• Red color means that there is an issue with that specific tag that needs to be addressed immediately. Click on the tag shown in red to find out what is the issue and how to fix it.
• Yellow color means minor issues with the implementation and needs to be corrected immediately otherwise we might find tracking discrepancies.
• Blue color means non-standard implementation has been found on your website. Though it is not an issue that should be fixed immediately, you can look into it and follow the standard way of implementation.
• Green color means all the tags found on your website are working as expected.

Additionally, you can click on each tag to view what information is collected.

To understand more about the Google Tag Assistant extension, refer to my article: Google Tag Assistant Tutorial

However, there are three shortcomings of Google Tag Assistant:

1. It can’t identify and validate tags across a website.
2. It doesn’t work for non-Google tags
3. It can’t identify tags that don’t fire (as they are either broken or waiting for an event to occur first)

Ghostery

Ghostery is a Chrome extension through which you can identify all the tags (both google and non-Google) which fire on a web page.

This extension also lets you block tags which could be useful in debugging tracking issues:

Just like Google Tag Assistant, it has its own shortcomings:

• It can’t identify tags across a website.
• It can’t identify tags that don’t fire (as they are either broken or waiting for an event to occur first)

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Tag Inspector

You can also use a tag inspector to conduct a tag audit on your website. This tool basically helps us  understand below  by running an audit on our website:

• What are the tags on your site?
• On which pages are these tags present?
• Which pages have missing tags?
• It also provides how the tags are implemented (in source code, or through tag management system)

They have free plans and paid as well. Free is limited to 50 or fewer pages. You need to register with your business email and you can start your scan. It’s basically a three-step process. 

Step-1:  You need to register with your business email and click on the “Start a new scan” on the top right side.

Step-2: Now provide the URL of your website and click on the next step.

Step-3: In the second step, based on your scanning requirements, you can enable to include subdomains, select specific user agents like Chrome, Firefox or region. Click on ‘Next step’.

Step-4: Click on ‘Begin scan’ and Tag Inspector will begin scanning your pages.

Step-5: Now your report will be ready with a  summary of how tags are loaded on your site. You can also export the report.

In the results, you can see the tags found on the website and how they are loaded.

Manual Tag Auditing

I manually search for a tag on a web page if it is not picked up by Google Tag Assistant or Ghostery. Generally, this happens when a tag is broken and thus can not be fired on page load.

For example, if your GTM container code is broken (maybe due to formatting issues) then it won’t be picked up by Google Tag Assistant. In that case, you look into the source code of the page, search for ‘gtm.js’ file to find the location of the GTM container code and determine what is wrong with the code.

I also do manual tag auditing while diagnosing ecommerce tracking issues.

Generally, the ecommerce tracking code is placed on the order confirmation page which can not be accessed directly through any third party tag auditing tool or website scraper.

In fact, any web page which is hidden behind a login or some sort of authentication system can not be scanned by any third-party tool and manual auditing is required.

Website Scraper Tools

Website scraper tools like Screaming Frog SEO spider can be used to identify tags across a website of any size.

I use Screaming Frog for tag auditing and for diagnosing tracking issues. Don’t be fooled by its name. It is much more than an SEO tool. This tool is capable of crawling your complete root domain to find out any issues with the tags implemented on the page. Although it is not a free tool, it is efficient in tag auditing for small and medium-sized websites.

It is a powerful website crawler through which you can identify any piece of code (and its occurrences) across a website of any size and it is not very expensive either. There are other better alternatives to Screaming Frog, when it comes to tag auditing but they will cost you thousands of dollars a year, a price not many are ready to pay.

Also, no paid tag auditing tool I know is able to audit Google Analytics tags the way I am going to show you in the next few minutes.

My tag auditing system will help you in identifying different types of Google Analytics trackings installed on a website like:

• Event Tracking
• Cross-domain tracking
• Social Interactions tracking
• User ID
• Custom dimensions
• Custom metrics
• and many more

Through my tag auditing system, you can:

1. Identify the pages where GA/GTM tags are found.
2. Identify the pages where GA/GTM tags are not found.
3. Identify the pages where data layers are found or not found.
4. Identify any tag whether it was fired or not.
5. Identify old GA configurations, the ones based on Classic GA traditional syntax or even older urchin syntax.
6. Identify non-Google tags and their location.
7. Identify any type of GA tracking
8. Scan any number and type of tags and technologies used on a website.

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Custom Google Analytics Tag Auditing System

Let us suppose you want to audit your website for the following tags and technologies:

1. Universal Analytics Tracking Code
2. Classic Google Analytics Configuration
3. Universal Analytics Cross-domain Auto linking
4. Universal Analytics event tracking
5. Facebook Custom Audience

You want to scan your website to find the pages which contain or do not contain these tags.

To do this follow the steps below:

Step-1: Open Screaming Frog SEO Spider tool and then go to Configuration > Spider:

Step-2: Uncheck following checkboxes to speed up your crawl:

1. Check images
2. Check CSS
3. Check JavaScript
4. Check SWF
5. Check External Links

By unchecking these checkboxes you will greatly reduce the crawling time especially if your website has got hundred or thousands of web pages.

Step-3: Go to the Configuration menu and click on ‘Custom’:

Step-4: Set up the following custom filters:

Note: The search strings (like analytis.js) that I have selected to find particular tags are based on the special characters which Screaming Frog SEO Spider can detect.

I am using the latest version of this crawler which is 3.3 and this version supports the following special characters:

1. = (equals to)
2. / (slash)
3. . (dot)
4. – (dash)
5. : (colon)
6. ‘ (single quotation mark)

Screaming Frog is not able to detect strings which contain any of the following special characters:

1. _ (underscore)
2. ( (parentheses)
3. [ (bracket)
4. ? (question mark)

Step-4: Now start the crawl and once the crawl is finished, click on the Custom tab on the right-hand side:

Under the ‘Filter’ drop-down menu, you can see all the filters you set up before starting the crawl.

Select one of the filters from the drop-down menu.

You can now filter out all those web pages which contain or do not contain your specified tags.

You can then download the list into Excel by clicking on the ‘Export’ button and then update/remove the tag code from a page. 

Following is the list of tags along with their search string for easy reference:

Classic Google Analytics Tags

Universal Analytics Tags

Other Marketing Tags

Other article you will find useful: Cross domain tracking in Google Tag Manager

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