What is the Fixation Index (FI)?
The Fixation Index (FI) is a statistical measure used in eye-tracking research to quantify the stability of fixations during visual search tasks. It provides insight into how efficiently visual attention is allocated to a target.
How to Use This Calculator
- Enter the Total Number of Fixations made during the task.
- Enter the Total Fixation Duration (in seconds) - the sum of all individual fixations.
- Enter the Total Scan Path Duration (in seconds) - the total time from the first to the last fixation.
- Click the Calculate button to compute the Fixation Index.
Understanding the Results
The Fixation Index is expressed as a percentage:
- Higher FI values (closer to 100%) indicate less stable fixations and more frequent microsaccades or attentional shifts.
- Lower FI values suggest more stable fixations and sustained attention.
Applications
The Fixation Index is widely used in various fields:
- Human-computer interaction to evaluate user interface usability
- Reading research to assess reading efficiency
- Marketing research to understand visual attention to advertisements
- Medical diagnosis for conditions affecting visual attention
- Industrial design to optimize visual guidance in interfaces
Interpretation Guidelines
While the exact thresholds may vary by task, general guidelines suggest:
- FIs below 20%: Excellent visual search efficiency
- FIs between 20-40%: Good visual search performance
- FIs between 40-60%: Acceptable but with some attentional variability
- FIs between 60-80%: Fair visual attention stability
- FIs above 80%: Poor visual attention stability