Preparations prior Assessment
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      Resolve poor or incomplete calibration of eye tracker

      Getting a good result from calibration can sometimes be difficult for a variety of reasons. Here we list examples for when calibration can be difficult and how to resolve that,

      Situations when result of calibrating is poor or incomplete 

      • The student wears glasses with thick frames and lenses. If this is the case, ask the student to keep their head still during calibration so that the glasses do not disturb the signal. Please ensure the lenses are clean.
      • Powerful light sources or strong sunlight may prevent the eye tracker from properly detecting the eyes. Move the equipment to a darker room, move away from windows or close any blinds which might be causing the issue.
      • The student has difficulty focusing on the moving circle. Encourage the student as they try to follow the moving circle around the screen with their eyes. They always need to stay focused on the circle even though they know where it is going, and they must continue to watch the circle as it stops in each corner.
      • The student may have a visual impairment, or they may have challenges around remaining focused.
      • Sometimes, for unknown reasons, it can be difficult to achieve a good calibration and it can be problematic despite several attempts. If this is the case, poor calibration must be accepted. Continue with the test and add a comment at the end. It is still possible to get a result despite a poor or incomplete calibration. Try a maximum of three times before continuing with the test.

        Examples of different quality calibration results:

        Optimal

        Two lines inside all circles

         

        Intermediate

        Lines within 4 out of the 5 circles

         

        Poor Calibration

        Lines are too long outside of the circles. Only accept this result after trying to calibrate a maximum of three times. Add a comment at the end of the test.

         

        Incomplete Calibration

        The two circles at the bottom are not visible as they lack lines. This means the pupil’s eyes were not detected at these points. Check positioning! Only accept this result after trying to calibrate a maximum of three times. Add a comment at the end of the test.

        Click here for more information about calibration.

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