What is intraclass correlation in statistics?
In statistics, the intraclass correlation, or the intraclass correlation coefficient (ICC), is a descriptive statistic that can be used when quantitative measurements are made on units that are organized into groups. It describes how strongly units in the same group resemble each other.
What does the ICC measure?
The ICC is a measure of reliability, specifically the reliability of two different raters to measure subjects similarly [12, 13]. Inter-rater reliability is important as it demonstrates that a scale is robust to changes in raters.
How do you calculate intraclass correlation in Excel?
How to Calculate Intraclass Correlation Coefficient in Excel
- Step 1: Create the Data. Suppose four different judges were asked to rate the quality of 10 different college entrance exams.
- Step 2: Fit an ANOVA.
- Step 3: Calculate the Intraclass Correlation Coefficient.
What is a good ICC value?
ICC Interpretation
Under such conditions, we suggest that ICC values less than 0.5 are indicative of poor reliability, values between 0.5 and 0.75 indicate moderate reliability, values between 0.75 and 0.9 indicate good reliability, and values greater than 0.90 indicate excellent reliability.
How is ICC calculated?
The ICC serves as a quantitative estimate of this aspect of reliability. Very generally speaking, the ICC is calculated as a ratio ICC = (variance of interest) / (total variance) = (variance of interest) / (variance of interest + unwanted variance).
Is Cronbach’s alpha the same as ICC?
Cronbach’s alpha is identical to the intraclass correlation coefficient (ICC), when the ICC is calculated using either the two-way mixed consistency or two-way random consistency models.
What does high ICC mean?
A high Intraclass Correlation Coefficient (ICC) close to 1 indicates high similarity between values from the same group. A low ICC close to zero means that values from the same group are not similar.
How do you use ICC in SPSS?
Run the analysis in SPSS.
- Analyze>Scale>Reliability Analysis.
- Select Statistics.
- Check “Intraclass correlation coefficient”.
- Make choices as you decided above.
- Click Continue.
- Click OK.
- Interpret output.
What is a high ICC?
How do you calculate intraclass correlation in SPSS?
What does a high ICC mean?
What does a negative ICC mean?
Negative ICC estimates are possible and can be interpreted as indicating that the true ICC is low, that is, two members chosen randomly from any class vary almost as much as any two randomly chosen members of the whole population.
How do you do the ICC?
Determine if you have a population of raters. If yes, use ICC(3), which is “Two-Way Mixed” in SPSS.
…
Run the analysis in SPSS.
- Analyze>Scale>Reliability Analysis.
- Select Statistics.
- Check “Intraclass correlation coefficient”.
- Make choices as you decided above.
- Click Continue.
- Click OK.
- Interpret output.