Relative percent difference

{
  "id": "MLC-T-ENV-023703",
  "term": "Relative percent difference",
  "field": "Environment",
  "definition": "A measure of precision, calculated by: Rd% = [X₁ - X₂]/Xave x 100 where: X₁ = concentration observed with the first detector or equipment; X₂ = concentration observed with the second detector, equipment, or absolute value; and Xave = average concentration = ((X₁ + X₂) / 2) The relative percent difference (RPD) and coefficient of variation (COV) provide a measure of precision, but they are not equal. Below are example duplicate radon results and the corresponding values of relative percent difference and coefficient of variation. See also Coefficient of variation (COV)",
  "abbreviation": "RPD",
  "subject": "Air",
  "references": [
    "Radon Glossary of Terms"
  ],
  "url": "https://mlchart.com/terminology/environment/relative-percent-difference/"
}