Want an easier way to debug analytics/doubleclick/tagmanager tracking? use a HTTP monitor.
I know it sounds counterintuitive, “that’s so much harder!” you cry, but actually for a complex website it can be much easier, especially if you’re doing cross-browser testing and want to make sure everything is firing correctly.
I use Charles – http://www.charlesproxy.com/download/ – since it’s easy to configure, when you first open it, it will set up the proxy for you, then it’s only running while Charles is open.
Once you have it installed and open, you’ll see when loading a page in a browser, it will fill the window with all http requests. (theres a red record button so you can pause it, and there’s the trash for clearing the window).
To the right of the filter field click the “Settings” button and tick on the option that “Filter uses regex”, then in the filter field enter “googletagmanager|doubleclick|google-analytics”
In the sequence area you should see the order everything loaded, and you should see the _utm.gif, /collect or /pagead/ items.
If you click the relevant item like /collect… go into the “Request” tab, and look at the “Query String” section, you’ll see what was tracked.
For analytics, if you’re unsure what each specific item in the query string is, you can read more here – https://developers.google.com/analytics/resources/articles/gaTrackingTroubleshooting#gifParameters / https://developers.google.com/analytics/devguides/collection/analyticsjs/field-reference
This works for any analytics package that tracks using query strings, so long as you’ve included it in your filter.