Enter the individual test scores, individual criterion measures, mean of the test scores, and mean of the criterion measures into the calculator to determine the validity coefficient.

## Validity Coefficient Formula

The following formula is used to calculate the validity coefficient.

VC = Σ((X - Mx) * (Y - My)) / sqrt((Σ(X - Mx)^2 * Σ(Y - My)^2))

Variables:

- VC is the validity coefficient
- X represents the individual test scores
- Y represents the individual criterion measures
- Mx is the mean of the test scores
- My is the mean of the criterion measures

## What is a Validity Coefficient?

A validity coefficient is a statistical measure used in psychometrics to determine the extent to which a test, scale, or measurement tool accurately measures what it is intended to measure. It is a correlation coefficient between the test scores and the criterion measure, ranging from -1 to +1. A higher absolute value indicates a stronger relationship and thus a more valid test. It is used to assess the validity of a test and to make predictions based on test scores.

## How to Calculate Validity Coefficient?

The following steps outline how to calculate the Validity Coefficient.

- First, gather the individual test scores (X) and individual criterion measures (Y).
- Next, calculate the mean of the test scores (Mx) and the mean of the criterion measures (My).
- Next, subtract the mean of the test scores (Mx) from each individual test score (X) and subtract the mean of the criterion measures (My) from each individual criterion measure (Y).
- Multiply the differences obtained in step 3 for each pair of X and Y.
- Sum up all the products obtained in step 4.
- Next, calculate the sum of the squared differences between the test scores (X) and the mean of the test scores (Mx).
- Calculate the sum of the squared differences between the criterion measures (Y) and the mean of the criterion measures (My).
- Multiply the results obtained in steps 6 and 7.
- Take the square root of the product obtained in step 8.
- Finally, divide the sum of the products obtained in step 5 by the square root obtained in step 9.
- After inserting the variables and calculating the result, check your answer with the calculator above.

**Example Problem : **

Use the following variables as an example problem to test your knowledge.

VC: validity coefficient

X: individual test scores

Y: individual criterion measures

Mx: mean of the test scores

My: mean of the criterion measures