I have been associated with uncertainty calculations for quite sometime. Asia Metrology Program (APMP) took interest in unification of expressing the measurement results along with uncertainty. In those days the uncertainty components were divided according to source of errors. The errors were named as random and systematic errors. Hence components of uncertainty were named random uncertainty and systematic uncertainty. Around 1980, BIPM took initiative by circulating questioners to the countries who were members of Metre Convention. Every member showed keen interest in expressing the uncertainty in a harmonious way. A small but path-breaking documentwas produced in 1980, which emphasized that uncertainty is not of different kinds; there are only.