How to Calculate Test Accuracy Ratios

Test accuracy ratios help plant managers ensure precision tools are properly calibrated.
••• Stockbyte/Stockbyte/Getty Images

Many industries require exacting precision in their measurements. Whether a national laboratory or a machining workshop, operators need to know how reliable the measurements are for their tools. Organizations, such as the National Conference of Standards Laboratories or the National Institute of Science and Technology, describe the accuracy of a tool’s calibration – how precise the measurement of the tool’s precision is – using test accuracy ratios (TARs), sometimes referred to as test uncertainty ratios. Learning how to calculate test accuracy ratios allows you to ensure that you calibrate your equipment to industry standards.

    Determine the tolerance of the tool. Consult the manufacturer’s technical literature to find the tool’s accuracy. For example, a manufacturer may specify that the alignment of a saw is accurate to within 1/10-inch.

    Locate the tolerance of the calibration standard. Refer to the technical literature for the tool or standard if you do not have the tolerance readily available. For example, a laser distance meter might have an accuracy of 6/100-inch.

    Reduce the ratio of calibration standard to tool accuracy. Divide the accuracy of the tool being calibrated by the accuracy of the calibration standard. For example, .1 divided by .006 equals 16.667. Express the result as the test accuracy ratio, such as 16.667:1.

Related Articles

How to Calculate Acid Test Ratio
How to Calculate the Diameter of a Circle From a Linear...
Test Your Knowledge on Middle School Science
How to Convert cSt to SUS
How to Convert mm Hg to in Hg
How to Convert Candle Power to Lumens
How to Calculate KVA to MVA
How to Convert Taper to Degrees
How to Convert HP to BTU/hr
How to Calculate MBH
How to Calculate Volume of a Rectangular Prism
How to Compare Ratios
How to Convert Inches to 16ths of an Inch
How to Test Electrical Conductivity
How to Convert PPM to NTU
How to Convert 220 Celsius to Fahrenheit
How to Find the Missing Side of a Right Triangle
How to Convert Metric Tons to Cubic Meters
How to Find the Area & Width of a Rectangle
Characteristics of Aquatic Plants