I am in a similar situation, where a few months ago the deductions were less than 1.5%, and now in the past three months over 5%. Nothing changed about my website and/or the nature of the traffic (90% organic).

@pubpolicycomms, care to shed some light on this issue?

Welcome sam77am to Webmaster World.

Usually I get regular debit of 20% to 30% which is huge for me

You are responsible to ensure that traffic coming to your sites is valid traffic. 20 to 30% is a high value for invalid click deductions, If I were you I would be worried about having the full account suspended. To locate invalid traffic you should look for pages that have abnormally high volumes of traffic, and/or ad clicks and then verify to see where the traffic is coming from and ensure that the traffic is in fact humans and not bots. If you finally do identify the sources of the invalid traffic, you then need to block it, by blocking the ips and by whatever other methods are appropriate.

my CTR is also not more than 6%.

This also seems very high, I would investigate to see if any specific pages are pushing this value up.

one is having organic traffic and for other domain I buy traffic

Buying traffic and monetizing with Adsense is generally not profitable, unless you are buying traffic from spurious sources, in which case this traffic may be the root of your problems.

Again at the rate they are deducting invalid clicks I would be more concerned about loosing the account than the 20 or 30%.

From experience the majority of posters here report end-of-month invalid traffic deductions at 2-5% of total earnings. Mine hovers around 2-3%. If you're losing 20-30% then there's likely something wrong with your traffic. It could be that you're purchasing traffic or that traffic is coming from dubious sources (e.g. click farms, bot attacks, VPNs). As @NickMNS says, I'd investigate it immediately before it catches G's attention and you lose 100% of your account.

@sam77am - if you determine that the "invalid traffic" is due to malicious bot activity, you can find a lot of useful information in the Search Engine Spider & User Agent ID Forum [webmasterworld.com]

And you get assistance with blocking code in the Apache Code Forum [webmasterworld.com]

Thank you for the replies guys. I understand that this might be happening due to invalid traffic from different sources however, one of my site has only organic traffic from search engine (up to 90%) but I see 15-20% deduction for that site account too.
I have investigated it already in past 4-5 months and made several changes in traffic sources too but not able to find any invalid source of traffic.
Further, I see that traffic sources, websites content are same so, no reason of invalid traffic source suddenly.

I guess G target account of some publishers and debit the funds randomly. When I ask them to provide date/period of invalid traffic activity they never share the same.

thanks,

Much of this is based on mobile ... what is VIEWED and g's determination of whether ad units appeared or not. Their sandbox, their rules and not much you can do about that.

The transparency is pretty opaque at the moment. Grin and bear it.

randomly

No.

websites content are same so, no reason of invalid traffic source suddenly.

That's not the same. It could be that Google has now gotten better at detecting invalid traffic, and you previously got away with it.

Any CTR above 3% is suspicious and above 4-5% is not normal.

Unless you are looking at raw log files, it's easy to miss a lot of bot traffic. And just because you have a lot of bot traffic doesn't mean it's your "fault" or that you caused it. I think something like over half the internet's traffic is non-human now anyway.

My percentage of invalid clickery was going up and up, and it was getting pretty tiresome. We did a lot of manual blocking, but it was like playing whack-a-mole; you can really only block them AFTER you detect it - i.e. it was reactive, not proactive. And as soon as you block it one place, it pops up from somewhere else.

Now, I'm not saying this will work for everyone, but we ended up putting all the sites into CloudFlare in March, and blocking a bunch of countries (Russia, China, Ukraine, etc) that would have no reason to come to my US-States oriented websites, and my invalid click rate has gone down to 1% or less ever since. So that might be worth a try. I previously had some issues with CloudFlare some years ago, but it seems to be doing a much better job these days. I'm assuming the technology has gotten better. Anyway, I'm pretty happy with it. It doesn't cost anything to try it out for a month or two and see if it helps bring down your invalid activity.

and above 4-5% is not normal

Ok, I'll go first, I have a "not normal" niche site that has averaged 4.66% so far during 2017, 5.88% since June 1st, 8.05% the last couple of weeks and as far as G let's us go back to 2012 ... 5.91%.

I wish I could replicate that CTR on other sites which are all using the same template and ad positioning.

One thing that I feel makes a difference with this site is that it is not only niche but aso local plus its EPC is way above my overall average.

I tried different domains in last 7 months but deductions are still there.

I run both kind of sites where one is having organic traffic and for other domain I buy traffic.

Speaking as a rank outsider, I gotta say that this sounds as if G### has gotten wise to whatever it is you’re running, and it may be time to rethink your business model.

This may be of interest, Google's best practices for buying traffic.
[support.google.com...]

Any CTR above 3% is suspicious and above 4-5% is not normal.

I've had a steady CTR of 5-6% for the last 14 years. I've met with numerous Adsense reps over the years and none had a problem with that rate.

@sam77am hey are u still your adsense account running fine? as i also got the same problem my earnings deducted 10% of july 2017 as an invalid traffic , please reply

Google took 30% of my July 2017 earnings due to invalid activity. The only thing that I changed was adding link ads. Even though the ads are clearly marked, I am going to remove them. My site rarely ever has a CTR over 1%. My base earnings for July were almost identical to those of June. I did have the link ads on in June, but my clawback was only 53 cents with the same amount of traffic and basically about the same amount of clicks. SO...link ads are coming off today!