“…O SPI framework & Practice [172], [199], [215], [220], [246] -- [179], [196] --- [122], [123], [131], [141], [142], [153], [154], [156], [163], [173], [175], [181], [191], [201], [214], [216], [223], [230], [251], [259] - [133] [127], [140], [150], [168], [210], [217] [239] - [226] R Tool [125], [126], [134], [155], [165], [180] measurement perspective is the least reported one. SPI initiatives that involve Six Sigma are mostly focused on the "Project" and "Project & Product" perspective.…”