An intraclass correlation coefficient (ICC) is used to determine if items (or subjects) can be rated reliably by different raters.

The value of an ICC can range from 0 to 1, with 0 indicating no reliability among raters and 1 indicating perfect reliability.

This tutorial provides a step-by-step example of how to calculate ICC in Excel.

**Step 1: Create the Data**

Suppose four different judges were asked to rate the quality of 10 different college entrance exams. The results are shown below:

**Step 2: Fit an ANOVA**

In order to calculate the ICC for these ratings, we first need to fit an **Anova: Two-Factor Without Replication**.

To do so, highlight cells A1:E11 as follows:

To do so, click the **Data** tab along the top ribbon and then click the **Data Analysis** option under the **Analysis** group:

If you don’t see this option available, you need to first load the Analysis ToolPak.

In the dropdown menu that appears, click **Anova: Two-Factor Without Replication** and then click **OK**. In the new window that appears, fill in the following information and then click **OK**:

The following results will appear:

**Step 3: Calculate the Intraclass Correlation Coefficient**

We can use the following formula to calculate the ICC among the raters:

The intraclass correlation coefficient (ICC) turns out to be **0.782**.

Here is how to interpret the value of an intraclass correlation coefficient, according to Koo & Li:

**Less than 0.50:**Poor reliability**Between 0.5 and 0.75:**Moderate reliability**Between 0.75 and 0.9:**Good reliability**Greater than 0.9:**Excellent reliability

Thus, we would conclude that an ICC of **0.782** indicates that the exams can be rated with “good” reliability by different raters.

**A Note on Calculating ICC**

There are several different versions of an ICC that can be calculated, depending on the following three factors:

**Model:**One-Way Random Effects, Two-Way Random Effects, or Two-Way Mixed Effects**Type of Relationship:**Consistency or Absolute Agreement**Unit:**Single rater or the mean of raters

In the previous example, the ICC that we calculated used the following assumptions:

**Model:**Two-Way Random Effects**Type of Relationship:**Absolute Agreement**Unit:**Single rater

For a detailed explanation of these assumptions, please refer to this article.

Hello!

It is an elegant way to get the ICC. Thank you! Could you show us the syntax for its CI95% as well?

How can i determine the 95% Confidence interval for the ICC value?