Calculating the Content Validity Ratio (CVR) is an important step in tool development, particularly in the process of validating items for inclusion in a psychometric tool. CVR quantifies the extent to which experts agree that an item is essential for measuring the construct of interest. Here's a step-by-step guide on how to calculate CVR:

1. Define the Panel of Experts

Assemble a panel of subject matter experts who are knowledgeable about the construct being measured. The number of experts can vary, but a minimum of 5 to 10 is common for reliable results.

2. Develop and Present the Items

Present the items (questions or statements) to the experts. For each item, ask the experts to rate its necessity for measuring the construct on a scale, typically:

• 1 = Not necessary
• 2 = Useful, but not essential
• 3 = Essential

3. Collect Expert Ratings

Collect the ratings from all experts for each item. The goal is to determine how many experts consider each item to be essential.

4. Calculate CVR for Each Item

Use the following formula to calculate the CVR for each item: CVR=(𝑛𝑒−𝑁/2)𝑁/2CVR=N/2(ne​−N/2)​

Where:

• 𝑛𝑒ne​ = Number of experts who rated the item as "essential"
• 𝑁N = Total number of experts

This formula can be broken down into the following steps:

a. Count Essential Ratings ( 𝑛𝑒ne​ ):Count the number of experts who rated the item as essential (i.e., gave it a rating of 3).

b. Calculate the Numerator:Subtract half of the total number of experts from the number of experts who rated the item as essential: 𝑛𝑒−𝑁/2ne​−N/2

c. Calculate the Denominator:Divide the total number of experts by 2: 𝑁/2N/2

d. Compute CVR:Divide the result of the numerator by the denominator: CVR=(𝑛𝑒−𝑁/2)𝑁/2CVR=N/2(ne​−N/2)​

5. Determine CVR Significance

The CVR value can range from -1 to +1:

• A CVR of +1 indicates that all experts consider the item essential.
• A CVR of 0 indicates that 50% of experts consider the item essential.
• A negative CVR indicates that fewer than 50% of experts consider the item essential.

To determine whether an item’s CVR is statistically significant, compare it to a critical CVR value. The critical values depend on the number of experts and can be found in Lawshe's table of CVR critical values (1975).

Example Calculation

Assume you have 10 experts ( 𝑁=10N=10 ) and 7 experts rated an item as essential ( 𝑛𝑒=7ne​=7 ).

So, the CVR for this item is 0.4.

6. Evaluate Items Based on CVR

Compare the calculated CVR to the critical CVR value based on the number of experts. For example, with 10 experts, the critical value might be around 0.62 (based on Lawshe’s table). If the CVR is equal to or greater than the critical value, the item is considered to have acceptable content validity.

By following these steps, you can systematically assess the content validity of each item in your psychometric tool, ensuring that the items included are essential for measuring the intended construct.

To give reference

Singha, R. (2024). How to calculate CVR in multidimensional psychometric tool development? Retrieved from https://www.researchgate.net/post/How_to_calculate_CVR_in_multidimensional_psychometric_tool_development