I happen to be attending Online Marketing Summit 2010 in San Diego today. Just
finished listening to a panel of six experts on Web Analytics. A good part of
the conversation covered a topic of frequent concern here.

The consensus of these folks? If you are using multiple tools, don't even think
about trying to get them to give you identical results. The way the tools work,
differences in page load times, latency and all sorts of other variables that
are out of your control and for the most part invisible all contribute to
inevitable disparity. Accuracy is not the watchword.

Eric Petersen of WebAnalyticsDemystified said quite strongly that he recommends
not using multiple tools. Most such use, he says, arises from a lack of
understanding how to use a given tool properly or having chosen the wrong tool
initially.

Great stuff.