In our approach, we consider a bounce to occur when a unique visitor spends less than 5 seconds on a page, assuming both the load and unload events are successfully fired. While this method isn’t flawless, it provides a practical representation given the limited data we collect compared to other solutions.

If the unload event isn’t sent, we exclude the entire page view from bounce rate calculations. This is because, without the unload event, we cannot accurately measure the time spent on the page which will skew calculations.

You can learn more about what are load and unload events here.