Products
Webtrends Analytics 9.x
Cause
When looking at the overview for a particular site page the Average Time on Site metric is different then the Geo: Countries metric of Average Visit Duration.
Resolution
They are both providing an average, the difference being that geo:countries is segmented by Country vs the main page ( key metrics) is all site traffic averaged. These numbers are not directly comparable as the weighting changes. Attempting to average a group of averages will not provide mathematically accurate results.