Percent Agreement Calculator

| Added in Statistics

What is Percent Agreement?

Percent Agreement (or Percent Difference) is a statistical measure that quantifies how much two values differ relative to their average. It's commonly used to assess the reliability of measurements, compare duplicate results, or evaluate inter-rater agreement.

How to Calculate Percent Agreement

The formula for calculating percent difference is:

[\text{Percent Difference} = \frac{\lvert V_{1} - V_{2} \rvert}{(V_{1} + V_{2}) / 2} \times 100]

Where:

  • V₁ is the first value
  • V₂ is the second value
  • |V₁ - V₂| is the absolute difference between the values

Calculation Example

Suppose two lab technicians measured a sample and got 45.2 and 46.8 respectively.

Step 1: Identify the values:

  • First Value (V₁): 45.2
  • Second Value (V₂): 46.8

Step 2: Calculate the absolute difference:

[\lvert 45.2 - 46.8 \rvert = 1.6]

Step 3: Calculate the average:

[\frac{45.2 + 46.8}{2} = 46.0]

Step 4: Calculate percent difference:

[\text{Percent Difference} = \frac{1.6}{46.0} \times 100 = 3.48]

The measurements show a 3.48% difference, indicating good agreement.

Interpretation Guide

Percent Difference Interpretation
0% - 2% Excellent agreement
2% - 5% Good agreement
5% - 10% Moderate agreement
> 10% Poor agreement

Frequently Asked Questions

Percent agreement (or percent difference) measures how much two values differ relative to their average. A result of 0% means perfect agreement, while higher values indicate greater disagreement.

The formula is the absolute difference between the values divided by their average, multiplied by 100. This gives a symmetric measure that does not depend on which value is considered the reference.

Use this calculator when comparing two measurements of the same quantity, such as duplicate lab results, survey responses from different observers, or repeated experiments.

This depends on the field and application. In scientific measurements, less than 5% difference is often considered good agreement. In some industrial applications, less than 10% may be acceptable.