Calculating Saccade Amplitude

[Pablo Stock]

Hey all,

I am currently looking into how saccade amplitudes are actually calculated. I found this previous Thread and understand now how these are calculated. I still lack an understanding of exactly what I am calculating this on.

Let’s say I have a list of eye-tracking recordings where an identification algorithm has already been applied (e.g. velocity-based) to, so that the individual recordings in the list are labeled as fixation or saccades.

Now, I have two different understanding:

1. Is the saccade amplitude now calculated for each recording in the list, regardless of whether it is a fixation or a saccade? Taking the distance from current list item to the following list item?

2. Is the saccade amplitude calculated on the saccade area that lies between two fixations? For example, the recording in the list with index 20 is a fixation, then there are only saccades up to index 39 and then a fixation again from index 40. Would the saccade amplitude then be calculated holistically from index 20 to index 40?

Thank in advance! 🙂

(I apologize that the question is not specifically aimed at the Tobii products, but is more of a general metrics question.)

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