Knowledge
Metrology Dictionary
The complete VIM vocabulary — all numbered concepts of JCGM 200:2012 as faithful paraphrases with clause citations — plus clearly labeled practice terms from the GUM, ILAC, ISO and NIST guidance.
Gauge R&R
A measurement systems analysis estimating the variation due to the gauge (repeatability) and the operators (reproducibility), commonly expressed as a percentage of total variation or tolerance.
AIAG MSA manual · Statistics
Intermediate measurement precision
Measurement precision under intermediate precision conditions — the realistic "within-lab, over months" figure that belongs in most uncertainty budgets.
VIM (JCGM 200:2012) 2.23 · Statistics
Intermediate precision condition
A condition set spanning the same procedure and location over an extended period, allowing other factors (operator, reference standard, time) to vary.
VIM (JCGM 200:2012) 2.22 · Statistics
Measurement bias
The estimate of a systematic measurement error — typically the difference between the mean of repeated indications and an accepted reference value.
VIM (JCGM 200:2012) 2.18 · Statistics
Measurement precision
Closeness of agreement between indications or measured values from replicate measurements under specified conditions — usually expressed as a standard deviation, variance, or coefficient of variation.
VIM (JCGM 200:2012) 2.15 · Statistics
Measurement repeatability
Measurement precision under repeatability conditions — the tightest, most flattering precision an instrument and operator can show.
VIM (JCGM 200:2012) 2.21 · Statistics
Measurement reproducibility
Measurement precision under reproducibility conditions — what interlaboratory comparisons quantify.
VIM (JCGM 200:2012) 2.25 · Statistics
Measurement trueness
Closeness of agreement between the average of infinitely many replicate measured values and a reference value. Trueness relates inversely to systematic error, not random error.
VIM (JCGM 200:2012) 2.14 · Statistics
Metrological compatibility of measurement results
The property of a set of results for a stated measurand such that the absolute difference of any pair is smaller than a chosen multiple of the standard uncertainty of that difference — the VIM's formal test for "do these results agree".
VIM (JCGM 200:2012) 2.47 · Statistics
Normalized error (En)
The interlaboratory comparison statistic En = (x − X) / √(U²(x) + U²(X)). |En| ≤ 1 indicates agreement within expanded uncertainties; it is the standard scoring for calibration proficiency tests.
ISO 13528:2022 · Statistics
Repeatability condition of measurement
A condition set that includes the same procedure, operators, measuring system, operating conditions, and location, with replicates over a short period.
VIM (JCGM 200:2012) 2.20 · Statistics
Reproducibility condition of measurement
A condition set that includes different locations, operators, and measuring systems applying the same procedure to the same or similar objects.
VIM (JCGM 200:2012) 2.24 · Statistics
Z-score
A proficiency-testing statistic z = (x − X)/σ_pt comparing a participant result with the assigned value in units of the standard deviation for proficiency assessment; |z| ≤ 2 is conventionally satisfactory.
ISO 13528:2022 · Statistics