FAQ: How can I recover the Drift Correction from the EDF file?

[Sam]

This information is stored in the EyeLink Data File (EDF) recorded during a participant's session. To recover the Drift Correction information from an EDF, convert the EDF file to an ASCII file, using the VisualEDF2ASC utility (which comes installed with Data Viewer - this software requires no licensing to use, or an alternative can be download here). Once the EDF file has been converted to a text file, open the file in a text editor, and look for the appropriate validation information. Look for a line similar to the following line:

Code:

MSG      8546331 DRIFTCORRECT R RIGHT at 512,384 OFFSET 0.26 deg

In the example above, the offset of the gaze was 0.26 degrees. 

Please bear in mind that, by default, this offset is not used to correct the calibration model on EyeLink 1000, EyeLink 1000 Plus and EyeLink Portable Duo systems. In other words for these systems the offset is simply recorded and not applied.