Occasionally, web analysts come across this question about the bounce rate calculation. In order to correctly calculate bounce rate, we must first understand the category of the website bounce. In this post, I want to discuss the website bounce process and the different methodology used for calculating the bounce rate.
calculating the bounce rate.
To start with, bounce rate is the coolest metrics because it can
give you a good understanding of the website performance. It shows how
many people visited only one page on your site. Here is the exact definition
from Wikipedia – “Bounce rate represents the average percentage of
initial visitors to a site who “bounce” away to a different site,
rather than continue on to other pages within the same site.”
There are different ways to calculate the bounce rate based on the category of the website bounce. Some use the time
spent on the site data and some use the single page visit data. Let’s
discuss all the techniques in detail.
Time on Site Methodology – Let’s imagine a person
is searching for holiday gifts and he/she types “holiday gifts ideas”
on Google. Fortunately, your website shows up at the top position out
of 928,000 search listings .
The visitor immediately clicks your site listing and lands on the home
page. After few seconds on the site (less than 10) the visitor is not
impressed with the site layout and shuts the browser window . This is considered as a bounce because the time spent on the site was too little to encourage clicks or engagement.
In our example, the visit was a single page (home page) visit.
However, there is a chance that someone lands on the site and quickly
clicks an internal link and then exits the site from that page. This
will not be considered as a bounce using the single page visit
methodology (coming up next). It is still considered as bounce using
time on site method because the time spent on site is less than 10
seconds (some use 5 seconds).
Time on site is a good indicator of the site bounce rate but
unfortunately most of the analytical solutions cannot spit out this
data directly. You have to use the time on site report and calculate
the bounce rate manually.
Single page visits – Just like the name suggests,
single page visit bounce rate calculation is based on each single page
site visit. It’s the percent of the time a visit is a single page
visit. This is the least recommended of all methods. The reason single
page visit is not considered as accurate bounce rate is it does not
count the second and the third visits to the site by the same visitor.
To understand why second and the third visit by same visitor is
important in the bounce rate calculation let me give an example– John,
an imaginary web surfer, visits a page A on my site and exits my site
form the same page A. This visit is counted as a single page visit.
Ideally, this is a bounce rate of 100% but the story does not end here.
John decides he should give my site another chance (lucky me ;). He
revisits the same day the same page A on my site but this time he also
visits pages B and C. Using the single page visit formula, John’s visit
is still a bounce, but in reality it is not due to his second visit.
Single page visit bounce can only be accurate when every visit on the site is a first visit.
Single page/Entry page – This is one of the
technique I recommend to calculate the bounce rate and it is also the
most popular bounce rate calculation. This method incorporates the
second or more visits data by the same visitor in the calculation and
eliminates the single page visit discrepancy.
According to this technique, a bounce rate is a percentage of total
number of single page visits divided by total number of entry page
visits for a given time period. Notice that the denominator is the
entry page visits.
Going back to our imaginary surfer John’s example, we see that page
A was the entry page two times and so the new bounce rate for the site
will be -
Single page visit / Entry page visit = ½ = 50% (compared to 100% using single page method)
Most web analytics tool, include this bounce rate report by default.
True bounce – Both, the time on site and the single page/entry page method are good
and each has its own advantage and disadvantage. I decided to use the
combination of both, and I call it as a true bounce. There is no direct
method or analytics reporting hack to spit out the combination bounce
rate, but I calculate true bounce by using averages of both bounce
I think the true bounce is as close as one can get calculating the
accurate bounce rate. This method not only considers the time spent but
also incorporates the single page visits and multiple visit criteria.
Segmentation – Site bounce rate is an important
metric but without segmentation you can never know the reason behind
the reason (why visitor bounced off from your site?). It is important
that you calculate the page level, campaign level and search keyword
level bounce rate.