A simple transformation of the , C*pm, Cpp can be regard as a process incapability index, provides an uncontaminated separation between information concerning the process accuracy and precision while this kind of information separation is not available with the C*pm. Recently, Kyung-seok Shin et. al. introduced an improved process incapability index C*pm by the transformation of the Cpmk. Accordingly, in this article process incapability index C*psk will be proposed by the transformation of the Cpsk . The motivation behind introduction of C*psk is that Cpsk has failed to overcome is that it cannot distinguish process of high conforming output proportions from those of low conforming output proportions. Process incapability index C*psk can identify a difference between two things by comparison on Cpsk and C*psk .EX>$_{psk}$.EX>$_{psk}$.