Eye Tracking vs. Mouse Tracking Analytics

Usability studies have been and continue to be a key method for testing and optimizing website usability.  Both laboratory eye tracking and remote mouse tracking studies offer businesses accurate and actionable results. Eye tracking, as used by top enterprises such as Google, uses cameras and specialist software to track where the eyes of internet users land on a webpage. Mouse tracking analytics follows the mouse movements of an internet user to simulate eye movement on a webpage.  Over the last few years, mouse tracking has greatly matured, developing features and achieving accuracy that make it a credible alternative to eye tracking.

Heatmaps created using traditional eye tracking (left) and mouse tracking (right)

Heatmaps created using traditional eye tracking (left) and mouse tracking (right)

Research has shown that when both methods of testing are conducted simultaneously, there is an 84%-88% correlation in the results1. In addition, both the eye and mouse move to relatively the same rhythm and focus in on the same page content2. Both eye and mouse tracking analytics deliver valuable information about how your visitors are engaging with your website. This is vital to work out what changes you need to make in order to benefit your visitors’ experience and your ROI.

Example of the mouse following the eye in the vertical direction on a google search page, plotting the Y coordinate against time. ©Google, 2008

Example of the mouse following the eye in the vertical direction on a Google search page, plotting the Y coordinate against time. ©Google, 2008

Pros & Cons

As with any process, each method of testing comes with its advantages and disadvantages.

Eye Tracking Analytics

Advantages Disadvantages
  • 100% accuracy. Find out exactly what the testers look at on the page.
  • Controlled environment. Your visitors are asked to carry out pre-determined tasks. You can therefore define exactly what to test and know the objectives of your testers.
  • Open Dialogue. Visitors can give in-depth feedback and answer any questions you may have, removing the guesswork regarding visitor motive and satisfaction.
  • Cost. Comes with an extremely hefty price tag, requiring specialist equipment and staff. The cost can increase with more participants and higher frequency of testing.
  • Limited scope. The number of participants, screen size measurements, and variety of participants is limited. Your data results are based on a small sampling of unique visitors.
  • Strong Observer Effect. Visitors know that their every move is being monitored, therefore cannot be expected to act naturally. High chance of the Hawthorne effect.

Mouse Tracking Analytics

Advantages Disadvantages
  • Natural environment. Tests take place in the visitors’ own home or office, providing accurate usability results with a wide array of browsers/operating systems/screen sizes etc…
  • No Observer Effect. Visitors navigate your website naturally, completely unaware they are being tested.
  • Global participation. Test visitors from all over the world. As long as there is traffic coming to your site, you can be continually testing, any time you want.
  • Low Cost. Mouse tracking analytics is a fraction of the cost of eye tracking, requiring no specialist equipment or skills. Free solutions are also available in the market.
  • No pre-define tests. You cannot specify what you would like to test. You have to rely on the visitors’ own objectives.
  • No research control. You cannot change or control the environment in which the tests take place.
  • No visitor feedback. You cannot directly ask your visitors questions about their experiences, and cannot know exactly what they are thinking.

There still exists a cloud of debate between eye and mouse tracking camps regarding the value of gauging subconscious thought versus that of actionable intent. Eye tracking does capture significantly more involuntary eye movement than mouse tracking, providing abundant information into a visitor’s subconscious.  However, the mouse tracking camp contends that, for many websites, it is more valuable to understand customers’ intent rather than their subconscious behavior, which is often subjective and can be misleading. Let us know what you think about the debate in the comments below.

What should I use?

In an ideal world, every website would use both eye and mouse tracking analytics, as each method delivers valuable and actionable information. Research conducted by Google3 concluded by saying that BOTH mouse and eye tracking should be used when evaluating and optimizing website usability. However, only some of the world biggest websites can afford to conduct regular eye tracking studies. This is therefore not a viable option for small or mid-size businesses, which should still rely on inexpensive and frequent mouse tracking studies.

We all deserve to know what our visitors think of our websites as well as with what elements our visitors are engaging, for your benefit and theirs.

References / further reading

1 http://portal.acm.org/citation.cfm?id=634234
2 http://www.stcsig.org/sn/PDF/Cooke_mouse_eye_tracker.pdf
3 http://research.microsoft.com/en-us/um/people/ryenw/proceedings/WISI2007.pdf – page 29