My favorite Google AdSense engineer is talking again in the Google AdSense Help forum. First he said that invalid traffic earnings were never really earned and now he goes on to explain why it is a waste of Google's time to investigate appeals towards invalid clicks issues.
Imagine, you are earning a nice side income with Google AdSense and all of a sudden, your earnings drop. Google tells you it is because of invalid traffic. You say what? And they send you a link to the invalid clicks and you say no way, this is not happening. Now what?
Well, according to Google AdSense Engineer, Google is not eager to investigate these reports. Why?
(1) Investigating invalid traffic is "often extremely difficult."
(2) It would require "hours of manual investigation by a specialist, many exchanges with the publisher, probably experiments over long periods of time."
(3) There is likely no "guarantee of success" in going this route. Meaning, even if they do tell you about the details of the invalid traffic, there isn't much you can do to prevent it and bring earnings back to the levels you had prior.
Here is what Google's Guillaume said:
About support, as an engineer I completely understand your frustration. That said, we should keep in mind that troubleshooting complex questions such as "why do I have invalid traffic" is often extremely difficult. Every time I look at an account to investigate an "I see a discrepancy of $X between estimated and finalized earnings" question on this forum, going further than verifying that the "because you have invalid traffic" answer applies would probably require hours of manual investigation by a specialist, many exchanges with the publisher, probably experiments over long periods of time, etc. all that without any guarantee of success. For instance, if I were to provide you with more detailed reports about invalid traffic, chances are that the reports would not give any information other than confirm what you already know (there was a peak of invalid traffic on March 13, and a sustained amount of invalid afterwards). It would not make the invalid traffic vanish, or reduce the discrepancies, or increase your earnings. What would you expect AdSense support to do that would really, concretely help while being realistic?
Forum discussion at Google AdSense Help.