The best way to ensure accurate data is to have an optimal participant setup and a good calibration. However, if a spatial mismatch between recorded fixations and the actual gaze location does occur, you can correct it in Data Viewer.
For best practices on setup, please see our video tutorials:
Before You Start: Back up your Data
Best Practice: Before making any manual changes, save a copy of your viewing session. This allows you to easily restore the original data if needed.
Method 1: Manual Fixation Adjustments
This tool is especially useful for reading data, as it aligns a group of fixations to their average Y-position.
Important Note: Event Data vs. Sample Data
Please be aware that these adjustments change the event data (the calculated properties of fixations and their associated saccades). The underlying raw sample data is never changed.
For best practices on setup, please see our video tutorials:
- EyeLink 1000 Plus Setup and Usage Video Tutorials
- EyeLink Portable Duo Setup and Usage Video Tutorials
Before You Start: Back up your Data
Best Practice: Before making any manual changes, save a copy of your viewing session. This allows you to easily restore the original data if needed.
Method 1: Manual Fixation Adjustments
- Step 1: Select the Fixation(s)
You can select fixations in several ways:- Single Fixation: Click on it in the Spatial Overlay view.
- Group (Spatial): Click and drag a box around the fixations in the Spatial Overlay view.
- Group (Inspector): In the Inspector > Data tab, CTRL/Cmd+click to select multiple individual fixations, or Shift+click to select a consecutive range.
- All Fixations: Press CTRL+A (Windows) or Cmd+A (Mac).
- Single Fixation: Click on it in the Spatial Overlay view.
- Step 2: Move the Fixation(s)
- With Arrow Keys: Select the fixation(s), hold down ALT (Windows) or Option (Mac), and use the arrow keys to move them.
- In the Inspector: For a single fixation, you can directly edit its Ave. X Position and Ave. Y Position in the lower panel of the Inspector.
- With Arrow Keys: Select the fixation(s), hold down ALT (Windows) or Option (Mac), and use the arrow keys to move them.
This tool is especially useful for reading data, as it aligns a group of fixations to their average Y-position.
- Select a group of consecutive fixations.
- Right-click on the selection and choose Drift Correct.
Note: The "Drift Correct" option may be grayed out if you have selected non-fixation events (like a message) or non-consecutive fixations.
- Alternatively, use the shortcut: CTRL+D (Windows) or Cmd+D (Mac).
Note: The correction will fail if any fixation deviates too much from the group's average Y-position. You can change this threshold in Preferences > Data Views > Batch Drift Correction Error Threshold.
Important Note: Event Data vs. Sample Data
Please be aware that these adjustments change the event data (the calculated properties of fixations and their associated saccades). The underlying raw sample data is never changed.