How do you calculate intraclass correlation?

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).

How do I interpret ICC results in R?

The value of an ICC lies between 0 to 1, with 0 indicating no reliability among raters and 1 indicating perfect reliability….ICC Interpretation Guide

  1. Less than 0.50: Poor reliability.
  2. Between 0.5 and 0.75: Moderate reliability.
  3. Between 0.75 and 0.9: Good reliability.
  4. Greater than 0.9: Excellent reliability.

How do you calculate R?

Use the formula (zy)i = (yi – ȳ) / s y and calculate a standardized value for each yi. Add the products from the last step together. Divide the sum from the previous step by n – 1, where n is the total number of points in our set of paired data. The result of all of this is the correlation coefficient r.

What is intraclass correlation coefficient value?

An intraclass correlation coefficient (ICC) is used to measure the reliability of ratings in studies where there are two or more raters. The value of an ICC can range from 0 to 1, with 0 indicating no reliability among raters and 1 indicating perfect reliability among raters.

How do you calculate ICC reliability?

ICC(1,k) As above, but reliability is calculated by taking an average of the k raters’ measurements. ICC(2,1) Each subject is measured by each rater, and raters are considered representative of a larger population of similar raters.

How do I calculate ICC in Excel?

How to Calculate Intraclass Correlation Coefficient in Excel

  1. Step 1: Create the Data.
  2. Step 2: Fit an ANOVA.
  3. Step 3: Calculate the Intraclass Correlation Coefficient.
  4. A Note on Calculating ICC.

Which ICC should I use?

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.

Can you calculate ICC in Excel?

For Example 1 of Intraclass Correlation, we can calculate the ICC as shown in Figure 3. First, we use Excel’s Anova: Single Factor data analysis tool, selecting the data in Figure 1 of Intraclass Correlation and grouping the data by Rows (instead of the default Columns).

Is Cronbach’s alpha the same as ICC?

Cronbach’s alpha is written as an ICC formula, using the well-known property that taking the average value of a number of ratings increases the reliability of a measurement. We illustrate with an example that the ICC formulas for average measurements of multiple raters and the SB formula give similar results.