My statcounter shows 2, 3 and sometimes 4 times more clicks then my adsense does. Nearly all my traffic is from google. An absolute majority are first time visitors. Adsense does not show any clicks at all ( I know that often they show numbers of invalid clicks with $0 ) Now I do know that i am not doing anything against google policies. So what gives?
I think this problem some difficulty oh. The best solution, or ask to call the past is better! So there is no question of the intermediate error
As an advertiser on AdWords' GDN, approximately 5% of my clicks are tagged as "invalid clicks". From the AdSense point of view I recall that their Terms and Conditions are draconian: "6. ... Google may at any time, in its sole discretion, terminate all or part of the Program, terminate this Agreement, or suspend or terminate the participation of any Property in all or part of the Program for any reason. In addition, Google reserves the right to terminate without notice any account that has not generated a sufficient number of valid clicks on Ads or Referral Buttons or valid impressions of Ads (in each case as measured by Google) for a period of two (2) months or more." BTW this is an AdWords forum
I'm afraid giving you an answer won't be of much help. As a manager of many accounts in many different verticals, the percentages vary quite a lot. Most of the accounts I manage also use only the search network, few use the display network. You just can't compare the two. But for what it's worth, I have clients with invalid clicks ranging from around 2% to 50%. That 50% is a local carpet cleaning company and definitely the exception, the next one about 17%, so I'd say a bit higher than 5% for me. I suspect with the large number of carpet cleaners, most people click on many ads, come back to the results screen and may click on the same ads in making their decision who to hire. That's where a good sales pitch on the landing page will make all the difference.