Hello-
An invalid click is not only a matter of the the click itself, but it depends of a series of signals, which are making a click more or less suspicious.
Among signals which "contribute" to the suspicion:
- Direct visit to a site, on a mobile phone device. On mobile devices, nearly no one types the URL of a site, so all direct traffic is adding a given level of suspicion.When you embed GA to your site, it helps Google figure out the origin of the visitor (which can be good or bad).
- Non residential IP, suspect because it can be a VPN, a dedicated servers, a bot, etc...
- Time on site, "before" clicking an ad, as well as the length of time the ad was visible before it's being clicked,
- Time and actions performed on the site of the advertiser,
and certainly lot more advanced methods, keep in mind that Google invests colossal resources , in order to track and profile anyone online. (again more if you have a mobile phone using Android, or/and if you are using Google Chrome browser)
If you delete your browser history, cookies, Google still has traces of you at its servers, even if your IP is changing, Google can cross match data based on the proximity of the different IPs you used. Worse, for example, when I use TOR, and even with the IP rotation, and exit nodes being at different countries, at some point Google is succeeding to guess my country anyhow.
[edited by: JorgeV at 11:12 am (utc) on Sep 30, 2019]