Verified Data uses a unique hybrid method that drives over 200 tests performed on your website and Google Analytics account data.
Firstly, the tool spiders your website looking for trackable content. The spider behaves just like a real visitor in that it waits for each page to load, then searches for clickable elements e.g. file downloads, outbound links, search boxes, submission forms etc., and clicks on them. The purpose being to listen for any signals being sent to Google Analytics. If the pageview or any of those click-throughs do not send a Google Analytics hit, then you know there is a problem.
Secondly, when you authenticate Verified Data with your Google Analytics account, API requests are conducted to query your data looking for oddities i.e. duplicate data, missing data, inaccurate and incorrect data. It also stress tests your governance as well as hunts for any traces of personal information – which of course you should not be collecting, both for Google Analytics terms of service and for GDPR compliance.
Note, Verified Data can only spider a website that you have Google Analytics access to. You cannot spider the entire web with it!