Time on Site Is a Bad Metric. Time on site is still often referred to as if it's a useful metric of a program's success. However, this metric is quite possibly one of the worst indicators of "engagement" because so many factors can increase or decrease it without having anything to do with a user's interest.
For example, if someone opens a page in a Web browser, then takes a 30-minute phone call before coming back to the page, that "time on site" is artificially higher. Or if someone can't find something and spends some frustrating minutes looking around on the site, the extra time spent doesn't indicate greater interest. In fact, the person may get increasingly annoyed at the site and never come back.
Other factors decrease time on site artificially -- for example, the person found what they were looking for immediately through site search. The person was very satisfied and left the site after completing a mission.So, what should you measure? Fou suggests new metrics that indicate user interest and intent like
Takeaway: there are no benchmarks for this metric. Drop it entirely as a success metric.--Read more on ClickZ.
Take a look at what you are measuring, and make sure that it makes sense.
- On-site search. Are your visitors looking for something specific on your site?
- Time they spend with a piece of content -- not just on the site in general. Are they spending time with a specific piece of content?
- Site bounce rate (lower is better). Are people on your site finding that they were looking for?
- Percentage of repeat visits. Do users find your site useful or valuable enough for them to come back?--Again, read the whole thing on ClickZ.