I was just checking the number of page views with Urchin stats for one of my websites and noticed something odd. Urchin is telling me the the average number of page views for site X is 3,912 per day. However Google's AdSense Stats never seems to get over the 1,000 page impression mark for that site. And before someone asks, there is AdSense on every page of the site. What are the reasons for this discrepancy? The only thing I can think of is that people are entering the site and clicking another link or the back button before Google can serve adds.
Based on the asssumption that "urchin stats" are accurately displaying the pageviews - the only possibility I can fathom is that many users to your website may have javascript disabled or as you say hit the back button bfore the page/ads loads.
Hi, don't forget that a swf or css files are considered as pages by Urchin (it's the case with my sites). If you have a lot of them, maybe that can make the difference.