It’s important to understand that webcam eye tracking has unique technical limitation — it is sensitive to head and body movements.
To ensure as many valid sessions as possible, it is crucial that your test participants sit up straight and don't move during the experiment. Excessive movement during the time we collect gaze data almost always results in an invalid trial, therefore avoid tasks that may cause the participant to move.
We do recommend starting the experiment with instructions, followed by your media, and finishing with questions to ensure the participant is more focused and maintains proper posture throughout the eye tracking part of the trial.
When testing the effects of survey question placement, we saw an average usable rate decrease of 10% when survey questions are added before or in between media, therefore we recommend you save all your survey questions for the end of the experiment.
Optimal duration time
Try to keep the duration of instructions + media within 70 seconds. Studies have shown that the usable rate begins to decrease rapidly when the experiment length exceeds 70 seconds due to the likelihood of participants moving out of focus during the session.
Calibration check points
We insert calibration check points automatically to maintain the quality of the gaze data and increase the usable rate of each session. Studies have shown an average usable rate decrease of 15% when calibration was disabled.
Calibration: what is it and how it works
Minimal number of sessions
Quantitative studies require a larger sample size to obtain meaningful conclusions. We recommend to achieve the minimum of 30 usable sessions per media to maintain statistically stable data.
If there are any conflicts with your methodology, contact us and we’ll help advise you on the best solution.