Why does my paid search engine report higher click-throughs or hits than Webtrends?
There is no expectation that Webtrends' report data will match that from third-parties for reasons which include the following:
Webtrends does not know how the ad server calculates its data
Ads can be served on any site so the referring domain may not match that of the ad server
Webtrends can't know how many click-throughs from the ad server fail to reach the destination as a result of bad links, network issues, etc.
Webtrends can't know how many click-throughs are from visitors who do not accept cookies, which are required to populate report data.
Search marketing companies count hits while Webtrends counts visits. Multiple hits to different ads with the same campaign ID will not generate new visits if they are within the visitor's session timeout period, but will generate hits for the ad with the paid seach provider.
Filters on Webtrends' profiles and custom reports may potentially filter out visitors that arrived through a paid link.
These are just a few of the reasons that can have an effect on these measures. Webtrends' results cannot be compared with search marketing companies because this would assume the same methods and standards are being applied to the process. The way the data is collected, compiled, analyzed and reported is different, and between these differences and the other circumstances listed it is not possible for the numbers to be reconciled.
Webtrends is not auditing software and should not be used for that purpose. Attempting to do so diminishes the purpose of Webtrends, which is to provide "trending" data. It is statistical analysis and the data is accurate relative to what it's been configured to measure. Keep in mind that it is 100% accurate with respects to the data that is in the log files, correlated with any filters that might be applied at the profile or custom report level. The data that comes out can only be as good as the data that comes in. There might be other factors that are preventing the data from being logged correctly. Even if this is the case, however, there is still no way that Webtrends can be used to reconcile with external data.