Page Impression Discrepancies

Way too low...

[digitalv]

Can anyone explain why the number of page impressions in AdSense is so significantly lower than my site's actual traffic? I sent an inquiry to Google and it was basically ignored, they marked the ticket as completed but there was no answer in it. I even got the follow-up questionnaire asking about how was their answer.

Is there a movement to block these ads? Is anyone else experiencing this?

We're not talking about some statistically insignificant number here like a couple thousand impressions... The site I'm referring to receives more than 1 million page views per month, yet the "Impressions" section of AdSense never shows more than 230,000 or so. And the AdSense code is in a server-side include which is shown on every page, so it's not an issue of some pages missing the code.

I run both Google Analytics and IWEBTrack, both are showing about the same number of impressions (within a few hundred). Both of those services use Javascript for tracking, so it's not an issue of users with JS disabled and unable to see the AdSense ads because if that were the case then they wouldn't be tracked by these remotely hosted analytics services.

Anyone have any ideas?

[ecmedia]

In general AdSense impressions will be lower than actual page impressions (I am assuming that you have already discounted the fake traffic that all websites get from scrapers and other crooks) because ads will not be served to all visitors. Many advertisers limit the ads to specific zip codes or countries, for example. How much that difference is will depend on your visitor profile.