• Unofficial Google Analytics Blog, Tuesday, June 3, 2008 1 PM

Shawn Purtell offers long and short explanations for why the time-on-page and time-on-site metrics you get from Google Analytics (GA) need to be held under a magnifying glass. "Due to the way Time on Page/Site are measured, there is a certain amount of error that goes along with them," Purtell says. "Fortunately, there's a way to measure this error."

In short, the error stems from the fact that GA uses timestamps to record page visits, bounces and exits. If a user lands on Page A at 3:15, then Page B at 3:25, Google determines time spent on Page A as 10 minutes. But if a user exits a site after going to Page B, GA can't calculate how much time they spent there, because there's no tracking data on the next page--whether it's a competitor's site or something random like an email homepage.

This skews your time-on-page metrics for every page that gets recorded as an exit page--and could lead you to believe that Page B, for example, is a poor converter, has poor navigation, etc.--when it really is just not getting credit for how much time users actually spend on it.

Read the whole story at Unofficial Google Analytics Blog »