We are not concerned here with the first impression that a website visitor may get on seeing your web page in the Blink of an eye.  Rather it is about just how many visitors get to see that web page.  That number is the most simple of metrics to confirm how a web page is performing in traffic terms.  Here we explore how best to capture that number.

This article includes some data, which seems to go against the conventional wisdom.  You are encouraged to review what is said and do your own checks on whether the view here is more correct than the traditional view.

Web Page Visitor Traffic

We deal only with the simplest of cases here.  The world has become much more complex now since we have situations where one website can almost hi-jack other web pages as is now happening with the new DiggBar. 

The Diggbar Keeps All Digg Homepage Traffic On Digg.  That may well mean that such traffic is never credited to the actual web page the visitors thought they were visiting.  Michael Arrington certainly feels that this will increase Digg's overall traffic substantially. 

Unlike other short URL services, Digg doesn't simply redirect to the longer URL. It keeps you on Digg and shows the site being pointed to in an iframe wrapper. You can only get to the underlying URL by clicking on the X button on the top right.  The traffic that Digg records is thus lost to the website owner.

Even for much simpler websites, some question whether Page Views are all that meaningful.  Back in 2007, Richard MacManus was questioning whether the Tyranny of the Page View Is Nearly Over.

An AP report today states that Nielsen/NetRatings, one of the leading Internet stats services, will "scrap rankings" based on page views and replace it with how long visitors spend at websites. The reason is that online video and technologies such as Ajax "increasingly make page views less meaningful." We've known for some time, but it's big news if a major stats service like Nielsen/NetRatings officially degrades the importance of page views. Note that later in the AP article, it states that Nielsen won't be fully scrapping page views - they "will still provide page view figures but won't formally rank them".

Despite these criticisms, some simple measure of web page traffic can be a rapid indicator of better or worse website traffic.  You then need to identify what these visitors do on the website but the sheer number of initial visitors is a good starting point.

Using Adsense Data

Adsense is the system whereby Google delivers text-based Google AdWords ads that are relevant to given website content pages.

If most pages on a blog or website carry Google Adsense ads, then the Adsense reports give a very quick measure of traffic.  The figure to look at is what they call Page Impressions.  They define a Page Impression as follows:

A page impression is generated every time a user views a page displaying Google ads. We will count one page impression regardless of the number of ads displayed on that page. For example, if you have a page displaying three ad units and it is viewed twice, you will generate two page impressions and six ad unit impressions.

It is a very simple measure but it is easily found in the Google Adsense reports.

Google Analytics For More Precision

For more precise measures of website traffic, you need to be using Analytics software.  Google has a free system called Google Analytics, which many find works well for them.  One key measure of traffic is what is called Pageview, which is defined as follows:

A pageview is an instance of a page being loaded by a browser.  Google Analytics logs a pageview each time the tracking code is executed. This can be an HTML or similar page with tracking code being loaded by a browser, or an urchinTracker event that is created to simulate a pageview in Analytics reports.

How Do Adsense Page Impressions Compare With Analytics Pageviews? - The Traditional View

It is most unlikely that these two measures, Page Impression and Pageview, will be exactly equal for any particular web page for a variety of reasons.  The traditional view is that the Adsense Page Impressions number comes out lower and sometimes much lower than the Analytics Pageview number.

Amit Agarwal suggested the following reasons why Adsense Page Impressions and Google Analytics Pageviews Do Not Match.

There are several reasons why the hit count (or page views) reported by Adsense is lower than the numbers displayed by your stats package:

  1. Ad-blocking software (like AdBlock plus) or block Adsense scripts
  2. Adsense doesn't have enough ads for your page
  3. Browsers like Lynx (which won't run Javascripts) or older browser versions that don't support IFRAMEs
  4. Default timezone of your stats software is different from Adsense on US Pacific Time
  5. If a website is slow, users abort loading the webpage by pressing the escape key before Adsense ads appear.

Dave Taylor suggested similar reasons in answering someone who was seeing about 50% of page views creating AdSense impressions, and suggested the most important reason of all was because Google can't always fulfill a requested ad block with paid advertising.

Abe Olandres presented some similar findings in a comparison of Adsense Page Impressions vs. Actual Pageviews done back in 2006.  He found that the ratio between the Adsense page impressions and the stats pageviews for his tests were between 64% and 71%.

It certainly may be that, since these tests were done some time ago, the ratios have changed.  However the current picture is equally perplexing but in the other direction.

A Current Case Study of Adsense Page Impressions vs. Analytics Pageviews

The reasons measured earlier for differences between these two measures of traffic will still be there.  Remember the following as just some of the reasons for differences.

  • Whether some visitors have ad-blocking software
  • Whether Adwords ads are served to all visitors
  • Whether some visitors have javascript turned off
  • Whether some visitors click away before web pages have fully loaded
  • How different measuring systems count search engine crawlers (spiders /robots) - presumably all should be ignored.

However you assess these factors, it might be assumed that the Adsense Page Impressions should be somewhat comparable with the Analytics Pageviews.

That Is Not What The Results Show

The following results are actuals for the month of March 2009.  The figures shown are the ratio of the number of Adsense Page Impressions to the number of Google Analytics PageViews.  All web pages carried both Adsense ads and the Google Analytics javascript code.

  • For four WordPress blogs, the ratios were as follows: 1.33, 2.21, 2.44 and 2.55.
  • For a simple HTML based website, the ratio was 1.65.

In other words the Adsense Page Impressions were always higher than the Google Analytics PageViews and sometimes dramatically so. 

A Possible Explanation

In all cases, the Google Analytics javascript code is always inserted at the very end of the web or blog page as the last item in the footer.  If some visitors click away before the web page has fully loaded, then they would not be counted as Google Analytics PageViews.  The Adsense Ads appear early on the web/blog post pages.  The web pages load relatively fast so nevertheless this is a somewhat surprising finding.

Concluding Remarks

Even though the two parameters do seem to differ, the pattern does seem to be relatively constant over time.  So either parameter could be used as an ongoing comparative measure of web page traffic. 

If anyone has any other thoughts that would explain this significant difference, adding these in the comments would be most appreciated.  Even better, if you are able to provide comparable ratios for your own blog or website, then that would be most useful.  Are these results presented here a true reflection of the current situation or are they an aberration?  Do Adsense Page Impressions differ so much from Analytics Pageviews? What do you think?