Eye-tracking glossary

Eye-tracking metrics

Gaze point - a point of where a person was looking (a sample of eye-tracking data); webcams usually have a 30Hz sampling rate, which means that for webcam eye-tracking, you'll get about 30 gaze points each second.

Fixation - a series of gaze points, that are very close in terms of time and space - the user's gaze stops for long enough for a person to focus and process what this person sees; to determine, whether such a cluster of gazes is a fixation or not, fixation filter parameters need to be defined.

Saccade - the movement of a user’s eyes between fixation points (during which a person doesn't process what he/she sees).

Heatmap - graphical representation of data (density of gaze points) where values are represented as colors.

Recording - a video showing how the participant’s eyes were moving over items during the test - the moving circle appearing on the video represents an area where the participant was looking (gaze point) at this particular moment throughout the duration of the whole test.

AOI - Area Of Interest is an analytical, easy-to-use tool that allows calculating quantitative eye movement measures; if you draw a boundary around an area of a chosen image that interests you, you'll receive desired metrics:

• average TTFF (Time To First Fixation) - the amount of time that it takes participants (on average) to look at this area for the first time,
• average time spent - the amount of time that participants spent on average looking at this area,
• number of fixations within this area (more fixation means more visual attention),
• ratio - how many of all the viewers (for whom eye-tracking data is collected for the item) saw this area (left at least 1 gaze or fixation within the area);  
• average fixation duration - the time that the average fixation lasted for;
• average FFD (first fixation duration) - how long, on average, lasted the first fixation;
• number of gazes - how many gazes were registered within this AOI;
• average TTFG (time to first gaze) - how long it took the participants on average to first look at this area in seconds (when the first gaze sample was taken),
• average revisits - how many times (on average) participants looked back at this area (looked at it, looked away, and then looked back again); AOI visit is detected if there's a fixation within the AOI (or many fixations "one after another"),
• TTFC (Time To First Click) - the amount of time that it takes participants (on average) to click at this area for the first time,
• AOI size - expressed as the percentage value relative to the size of the entire image; it's recommended to make AOIs of at least 5-10% of the item size,
• AOI time range - the time for which the values of the AOI were calculated (you can set this time with the orange slider under the heatmap),

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Terms from RealEye pricing

Maximum study time - the total time of all items display, so, for a 10 minutes study time, within one study, it's possible to display i.e., 1 image for 10 minutes or 100 images for 6 seconds each, or 2 images - one for 8 minutes, the second one for 2 minutes, etc.

Data export - the possibility to download collected data in form of CSV files.

Team collaboration - more than one person can be assigned to the same account; team members can work on creating studies/ analyzing data at the same time.

Participant - a person that takes part in the eye-tracking study (opens the participation link) - needs to meet the requirements.