TS ISO 11843-3

TS ISO 11843-3 is the third part of the capability of detection series, and it addresses how to determine the critical value for the response variable when calibration data are not used. In this part, the methodology is based on the mean and standard deviation of repeated measurements of a reference state, for situations where the value of the net state variable is zero. In practical measurement work, that critical value serves as a decision threshold for distinguishing a real effect from ordinary measurement variation.

How the critical value relates to detection capability

In general technical terms, detection capability describes a method’s ability to distinguish a non-zero signal from background variation with confidence. A critical value is the threshold derived from reference-state observations and used to interpret whether a measured response is meaningfully different from zero. When calibration data are unavailable, the evaluation relies on the statistical properties of repeated reference measurements rather than on a calibration curve. This makes the standard relevant where calibration is impractical, limited, or not the preferred basis for decision-making.

Statistical basis used by this part

• Mean and standard deviation from repeated measurements of the reference state
• Situations where the net state variable is taken as zero
• Estimation of the critical value for the response variable
• A methodology intended for cases without calibration data

The standard sits within the broader field of metrology and statistical evaluation of measurement methods. Its cited references align with commonly used concepts such as measurement uncertainty, statistical distributions, and the trueness and precision of measurement procedures. In that sense, it supports decision rules for measurement results rather than defining a specific instrument, material, or test item.