How to Interpret Time on Site

How long a visitor stays on your website has long been considered a key indication of how successful that site is in attracting relevant visitors. The theory being that the longer someone spends on the site the more interested they are in what you have to offer.

But is it that simple?

Time on site or visit duration can be an indication of the level of interest or involvement that a visitor has with the website. It is also a good indicator of the success of a campaign or other promotional activity that brings visitors to your website.

Often a visitor may come to the website more than once before they purchase, register or make contact. Equally there may be some lag time (often called latency in web analytics speak) between the time that they first arrive and the time that they convert or purchase.

Almost universally when I work with a client on the issue of time on site the question is raised; well what if I leave my browser open overnight, have a cup of coffee, lunch, etc does that impact how long the web analytics tool shows as having spent time on the site.

This issue actually cuts to the heart of a fundamental problem with web analytics – the notion of what is a “visitor” and the assumptions that we use to determine this.

To understand how time on site works it is important to understand how this metric is calculated in your web analytics software.

The time that a visitor spends on the site is calculated as the difference between the recorded time of their last page (or file) request on the site and their first. There are two important concepts here:

1. All requests are recorded. However when a visitor spends a few minutes on a web page and then clicks on a link to download a PDF extra time may not be reported.

2. In the event that the visitor only views 1 web page there is no record of the time that they leave this page or close their browser. In this case the difference between their first and last page request is 0.

As time on site doesn’t account for the time spent reading (or ignoring) the last page in the session it can’t be said to be an accurate reflection of how visitors actually use the site. So leaving your browser open on a page doesn’t cause the average time on site to increase unless you click on another page. In this case each web analytics tool will have its own rules about when to terminate a session and start a new one. In most cases this is based on a gap of 30 minutes or more in the sequence of activities. So if you left your browser open on a page and went to lunch then returned in an hour to click on a link it would be counted as a new session or visit to the site.

Time on site is a good indicative and relative measure. For instance if you compare the difference in time on site for each campaign that you run, then you can see how each campaign compares in regards to the time on site that results.

Campaign 1: 2 minutes 30 seconds
Campaign 2: 4 minutes 5 seconds

If the average for all visitors to the site was 3 minutes 20 seconds we could reasonably infer that visitors from campaign 2 where more interested in the site than visitors in campaign 1. Also as campaign 1 had a lower time on site than the overall average, we could say that these visitors were less interested than the general visitors to the site.

As an absolute value time on site is just a number and one that should be treated carefully.

An additional factor is that time on site should be assessed as the average number of pages viewed during the session. In some sites such as online banking you are looking for lower time on site but the number of page views may be high depending on the tasks that are completed. In other sites like a newspaper you would be looking for high time on site with high numbers of page views as an indication of success as the revenue is tied to page impressions.

This is best illustrated in the following grid:

Page Views
High Low
Time on Site High A B
Low C D

The 4 quadrants are explained below. The selection of the appropriate quadrant will depend on both the site and the business goals associated with it.

Quadrant A: High time on site, high number of page views

May indicate a high level of interest and involvement with the site.
Could indicate high level of frustrations with visitors really having difficulties on the site.
Good Indicator for:

Where a high level of involvement is a key performance indicator. E.g. advertising based sites selling banners based on page impressions.

Poor Indicator for:

Where a site is supporting visitors who should be able to readily access information or perform a task in a short period of time. E.g. government and self service websites like online banking.

Quadrant B: High time on site, low number of page views

May indicate a reading behaviour pattern.
Lower number of page impressions may be a negative for advertising related websites
Good Indicator for:

Sites that require a lot of time to read and understand the contents of the site. E.g. a professional services company

Poor Indicator for:

Sites that sell advertising

Quadrant C: Low time on site, high number of page views

May indicate success for sites that require visitors to complete tasks quickly
Could indicate that visitors are lost in the site.
Good Indicator for:

Sites that require high involvement in short bursts. E.g. banking sites, online applications.

Poor Indicator for:

Complex websites such as those of government agencies.

Quadrant D: Low time on site, low number of page views

Positive: For sites that only provide a simple response or quick answers Negative:
Generally implies disinterest in the site
Good Indicator for:

Sites where visitors are seeking answers. E.g. search engines, directories, dictionaries, etc.

In this case repeat visitor behaviour is a crucial contributing factor and must be assessed as well.

Poor Indicator for:

Most websites.

Beyond this there are many other layers that need to be carefully interpreted to understand the value of time on site, however in general it is a good indicator of performance. For further details and assistance with understanding your website please contact Panalysis for a no obligation discussion of your requirements.


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