WAA Standard definition: Visit Duration
The length of time in a session. Calculation is typically the timestamp of the last activity in the session minus the timestamp of the first activity of the session.
When there is only one piece of activity in a session (a single-page visit or singleevent visit), no visit duration is typically reported.
This is a fine definition and one that I certainly agree on. BUT then comes questions on the subsequent metric that we could call “Visit Duration Average” – first question is what to name the metric and second question is on how to calculate the metric. Before concluding anything. Let us take a look at Google Analytics and IndexTools (because that is funny enough what I use here on my blog – still waiting for those Omniture blokes to call me ;-)
- 00:07:09 Avg. Time on Site (Google Analytics)
So first (and I am completely biased here) – I do not really think the Google Analytics “Avg. Time on Site” naming convention is clear enough confirming that we talk about a Visit (session).
Google Analytics discounts Bounces (or Single Page View Visits as the new WAA standard definitions calls it) and IndexTools includes ALL visits into the calculation. So to be clear, if we have:
2300 minutes spent on site
Remember that page tagging solutions like IndexTools and Google Analytics do not count time spent on site for bounces (Single Page View Visits). Thus in the above example the 2300 minutes are spent on 1000-300 = 700 visits. Even though we know for a fact that those 300 bounces (Single Page View Visits) in fact did spend time on the site.
- IndexTools = 2300 minutes / 1000 visits = A Visit Duration Average on 2.30 minute. (or Avg. Time per Visit 2m 30s as we would write it)
- Google Analytics = 2300 minutes / 700 visits = A Visit Duration Average on 3.29 minute. (or 00:03:29 Avg. Time on Site as my friends at Google write it)
In point of fact, I think both calculations are justified and I see a reason to include both of them. It might be a bit clumsy to start pre-segmenting visits (visits with MORE than 1 page view) as our friends from Google Analytics have done (sorry Avinash and Brian). Looking at a calculation where we discount bounces, we are actually just saying that we want to look at the, to some extent, more engaged users (those who decided to dig further into the site). I therefore prefer the original calculation (as Google Analytics used to have it as well) where we look at ALL visits. Then one can always segment to separate more or less engaged users from the others, whether that is page views or not.
As an example. Let us look at May 2007 (I can of course recreate these results with on the fly segments):
1 page views or more segment = 04.11 (the complete data set)
2 page views or more segment = 10.54
3 page views or more segment = 17.38
4 page views or more segment = 22.30
If you add another definition to your standard set about visit duration, I suggest you call it: “Visit Duration Average” and the calculation is the total length of time spent in all visits (sessions) divided by the total number of visits (session). Hereafter one can segment on page views or more intelligent engagement metrics.
- Google Analytics changes tack (iMEDIA connection)
- Google analytics- average time on site (leapfrogg)
- Google Analytics: Bounce Visits are excluded for Avg. Time On Site (Things and stuff)