Precision estimates produced by specially-designed ruggedness tests compared with those derived from collaborative trials, in relation to estimation of measurement uncertainty.

We have compared the reproducibility precisions provided by collaborative trials with precisions obtained from ruggedness tests specially designed to try to simulate between-laboratory variation. We found that the ruggedness tests underestimated the reproducibility variability consistently for those analytical methods requiring empirical calibration. The ruggedness tests provided on average a precision merely comparable with repeatability precision. This finding has implications for the estimation of uncertainty.