Explanation: why does "n.a." change?
'Time Viewed' changed to "n.a." after 10 minutes
How is it possible to watch a visitor be online for up to 10 minutes and then see their visit duration change to n.a.?
For a quick explanation, hover your mouse over the 'help' on the page you are looking at.
For technical explanations, there are two parts to the answer:
1. A visitor who has been online for several minutes suddenly turns to "n.a."
2. There are "n.a." visitors recorded in clickstreams from yesterday, or any data in the past.
1. If you have tracked some visitors for up to ten minutes, and then seen "n.a." appear, this is because we have set the minimum visit time at ten minutes, and an exit event was not recorded, so that a visitor is not registered as having left until a ten minute period has elapsed.
We receive a signal when a browser requests a page, but not always when the page is closed. So we chose ten minutes as a cut-off time, which is why you can track somebody for a few minutes & then their status changes to "n.a.". The standard to date, in this developing technology field has been 30 minutes. We feel that 30 minutes is too long to wait and find out if a visitor is still on site.
The method is to use the fact that a visitor clicks to a new page to mean that they have "closed" the previous page. Therefore, when a person looks at one page, and leaves that page open, until the 10 minute session has ended, their status will revert to "n.a.", as there will have been no exit event.
2. When you see "n.a." for a visitor who has come and gone more than ten minutes ago, it means that the visitor did not remain on the page long enough for the time to be recorded.
"n.a." shows that only an entry event has been measured. Basically, the problem is that the exit event was not measured probably because the user clicked away too fast. So the technical reason is that the event was simply not defined. As we are the only service using/offering this technology to measure time spent on pages (as far as we know we are the only company offering this), there is still work to be done in this area.
So the bottom line is that you have to wait out the ten minutes until you can know for sure what a visitor has done. So, if a person enters your site, and leaves immediately, they will remain "online" for ten minutes, until they are registered as having left.