It is clear that the average time spent on page 2 is more accurate, so we only excluded 15% of the visitors from our calculations as opposed to excluding 45% in the case of page 1.

How can we calculate time spent on the site? Figure 2-5 shows that the visitor entered the website at 6:00. The last interaction the visitor had with the site was at 6:10. We do not know exactly when the visitor exited the site, but we have to work with the data available to us. So, analytics will report the time this visitor spent on the site as 10 minutes. As you can see, there again is some inaccuracy in this reporting. The following formula shows how to calculate the average time all users spend on the site:

Table 2-7 shows how much time three visitors spent on a website. As you can see, the third visitor shows a time spent of 0. Should we include that visitor when calculating the average time spent on the site for all visitors?

So, should we count single page visitors as part of the “total number of visitors” in the preceding formula? The example demonstrates that we are artificially introducing inaccuracy to our reporting. In 2007, Google Analytics decided to remove these bounced visitors from total-time-on-site calculations. By doing so, you no longer could compare time on a site before and after the change in method calculation. For the sake of consistency over accuracy, the Google Analytics team decided to go back to including bounce visitors in their calculation of average time spent on a site.^[15] Our discussion of the accuracy of time spent on a page should not impact the importance of this metric, but rather should prompt you to consider and apply the metric with caution.

A high average time spent on a page indicates that visitors are either engaged by the content or struggling to understand it. There is a huge difference between the two. How do you determine which scenario is the case? Bounce rates, exit rates, and average time spent on a page help to answer this question. Pages with high bounce and exit rates indicate that visitors are not able to find what they are looking for, and thus they are leaving the site. We usually expect these pages to have a lower time-spent-on-page rate since visitors are leaving the site. High exit rates and high time-spent-on-page rates indicate that visitors are struggling with the page content. Although a high percentage of visitors are leaving, those who are staying are spending a long time trying to understand the content. This usually indicates that the page’s design, copy, and presentation need to be reevaluated.