standard deviation for proficiency assessment

symbol: $\upsigma_{\rm{PT}}$

https://doi.org/10.1351/goldbook.08130

Measure of dispersion used in the evaluation of results of proficiency testing.

Note: Not all proficiency testing schemes evaluate proficiency based on the dispersion of results.

Source:
PAC, 2021, 93, 997. 'Metrological and quality concepts in analytical chemistry (IUPAC Recommendations 2021)' on page 1041 (https://doi.org/10.1515/pac-2019-0819)