This guide is recommended for the purpose of evaluating test equipment that may be utilized in statistical process control, testing laboratories, and for in-process control of manufacturing operations.

Ask the question: What effect does the operator have on the measurement process? If possible, the operators who normally use the test equipment should be included in the study. If operator calibration of the equipment is likely to be a significant cause of variation, then the operator should recalibrate the equipment prior to each group of readings.

The test equipment should provide direct readings in which the smallest digit is no larger than one tenth of the tolerance of the characteristic being evaluated.

It is recommended that a test equipment repeatability and reproducibility study be a mandatory part of all test equipment purchases and that acceptance criteria be <10 % for certification and statistical process control (SPC) use.