Eye movements parameters
From the recorded eye movements the SW computes a number of quantitative parameters that can be described as temporal and spatial measures.
Temporal measures give information about the duration of the information treatment, indicate the time spent on the interface and identifies specifically the time spent for information research (saccades) and for information acquisition (fixations). Temporal measures can also show the centre of interest or the difficulties that a subject has encountered during the identification and the integration of information:

• the total time of permanence (Permanence time): indicates the time that user spends to process the whole page.
• the mean fixation duration (Mean fixation time): indicates the time that user spends to process what s/he is observing.
• the number of fixations (Number of fixations): it is linked to the effort of the user to process information contained in the zone s/he is observing.

Spatial measures, are spatial traces of the gaze’s displacement. The spatial measures are linked to the geometrical and structural characteristics of the interface and can reflect the visual difficulties or the problems of attention encountered by the users:

• the length of the scanpath (Scanpath length): it is a parameter independent of the contents and it is a productivity measure that can be used to define an optimal visual search that minimizes saccades amplitude.
• the percentage area covered by the scanpath (Covered surface).