Why are my Urchin 5 UTM sessions/pageviews different after upgrading from Urchin 4?

Overview

Customers deploying Urchin 5 may notice a difference in the session and pageview counts after upgrading from Urchin 4 to Urchin 5. While this may be attributable to a normal side effect of adopting a new technology, incorrect configuration is the most likely culprit. The most common reasons for the discrepancies in statistics are outlined below.

Common Mis-configuration Problems

  1. The "UTM domain" Profile configuration setting is incorrect; it is either not set or the value does not match the value used for the "_udn" variable in the __utm.js file in the document root of the website itself. This will result in no sessions or pageviews being recorded.
  2. The __utm.gif file is missing from the document root of the website, or is inaccessible due to permissions problems. This results in the hits to __utm.gif being recorded in the webserver log with a 404 (not found) status code. The end result is that no sessions or pageviews will be recorded.
  3. Some pages on the website are missing the SCRIPT line that calls __utm.js. This will be obvious if the Top Pages report from Urchin 5 is compared with the Top Pages report from Urchin 4. The Urchin 5 report will only list pages that have the SCRIPT tag, whereas Urchin 4 will list all requests for files that it deems to be pages.
  4. The __utm.js file in the website's document root has not been updated from the UTM-1 version supplied with Urchin 4 to the UTM-2 version supplied with Urchin 5. While this in itself should not directly affect the statistics, the UTM-2 __utm.js file is required for increased accuracy and population of the reports in the Client Parameters reporting area of Urchin. The updated UTM-2 version of the __utm.js file can be found in the "util/utm" directory of the Urchin 5 distribution.
Differences in Tracking Technology

  1. Urchin 5 only tracks pages that have hits with valid status codes (2xx, 302, or 304), and those pages must have the SCRIPT call to __utm.js embedded in them. Urchin 4 attempted to track pages even if they did not explicitly include the SCRIPT call. For further details, please read Urchin 3, 4, & 5 Reporting Differences.
Additional References

It is crucial that the components for UTM be installed properly in order to provide accurate tracking. Implementors of Urchin 5 are strongly encouraged to read the documents in the Visitor Tracking section of the Urchin Help Center, especially the document entitled Urchin Traffic Monitor (UTM) and the appropriate quick install guide for the webserver being used.