If you intend to do this then you'll also have to analyse the trend in the calibration data for the electrical safety analyser won't you? To asses how calibration of the analyser influences the measurements obtined, nevermind variatons in the device.

Another complication is that if different safety analysers are used for subsequent tests on the same device this means you'll have to analyse the calibration of each tester that tests have been performed each time the analyser is calibrated.

This would enable you to determine how the safety test results for a particular device have been inflenced by different analysers' measurement error or for variation in error between calibrations of the same safety analyser.

Some devices that have been developed for testing to DIN 0751, e.g. Gossen Metrawatt Secutest SIII medical safety tester, are based upon the recurrent test standard that's discussed in the Scope article - these instruments have the facility to include the measurement errors, i.e. measurement error, in the readings obtained.

This facility simplifies analysis of safety trends between calibrations of an analyser (assuming there is drift or adjustments are necessary) and between analysers of the same type, but with slight variations in measurement errors, I suppose.