©Fluke Calibration 2011    Basics Of Measurement Uncertainty for DMM Calibration      11 
Measurement uncertainty in 
metrology today… 
Measurement errors were not rigorously evaluated in all 
cases.  Often in industrial labs, accuracy ratio analysis 
(referred to as TUR’s or TAR’s or TSR’s) had been frequently 
used to evaluate the significance of the calibrator’s errors on 
the measurements.  Other errors were sometimes ignored. 
 
Individually analyzed, calculated, & documented measurement 
uncertainties are more thorough and are required to be 
considered - as stated in  
− ANSI/ISO/IEC 17025:2005 General Requirements for the 
Competence of Testing and Calibration Laboratories