Invalid clicks - at what level should I worry?

[nickreynolds]

Been an adsense publisher for quite a few years now. In the early days i was paranoid about getting banned although I wasn't doing anything that i knew to be wrong. Anyway my more recent complacency has been jarred by the deduction for october earnings for invalid clicks. Previous months it was <1% of earnings. Last month it jumped to around 8%.
I don't do any of the things you would worry about: dont click my own ads, none of my family or friends even know what my sites are, traffic is all organic. A few of my sites do generate a high ctr (up to 9%) and a highish cpc (they are in a niche that advertisers are throwing money at at the moment) although my overall account ctr is nearer 2%.
So - at what rate of invalid click deductions do i need to worry that my account may get closed?

[keyplyr]

Clickbots most often come from server farm ranges or compromised ISP accounts. However, almost any bot can cause invalid clicks, so be selective what agents you give access to your server.

Search Engine Spider & User Agent ID Forum [webmasterworld.com]

Server Farm IP Ranges [webmasterworld.com]

Blocking Methods [webmasterworld.com]

[keyplyr]

at what rate of invalid click deductions do i need to worry that my account may get closed?

I'm not sure there is an official statement from Adsense or Google expliciting identifying the threshold where invalid clicks would warrant action beyond removing them from you payments.

I suspect if Google was to reveal this information, it wouldn't take long for that metric to be exploited.