A relatively new approach to the problems of undercounting and overcounting of
server-based log file analysis described in Table 9.3 is to use a different browser-basedor
tag-basedmeasurement system that records access to web pages every time a page is
loaded into a user’s web browser through running a short script, program or tag inserted
into the web page. The key benefit of the browser-based approach is that potentially it is
more accurate than server-based approaches. Figure 9.7 indicates how the browser-based
approach works.
PERFORMANCE MANAGEMENT FOR INTERNET MARKETINGTable 9.2 Inaccuracies caused by server-based log file analysis
Sources of undercounting Sources of overcounting
Caching in user’s web browsers (when a user Frames (a user viewing a framed page with three
accesses a previously accessed file, it is loaded frames will be recorded as three page
from the user’s cache on their PC) impressions on a server-based system)
Caching on proxy servers (proxy servers are Spiders and robots (traversing of a site by spiders
used within organisations or ISPs to reduce from different search engines is recorded as page
Internet traffic by storing copies of frequently impressions. These spiders can be excluded, but
used pages) this is time-consuming)
Firewalls (these do not usually exclude page Executable files (these can also be recorded as
impressions, but they usually assign a single IP hits or page impressions unless excluded)
address for the user of the page, rather than
referring to an individual’s PC)
Dynamically generated pages, generated ‘on
the fly’, are difficult to assess with server-based
log filesFigure 9.7 Differences between browser-based and server-based measurement
systems
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