Page 117 - Six Sigma Advanced Tools for Black Belts and Master Black Belts

OTE/SPH
OTE/SPH
August 31, 2006
JWBK119-08
Current and Future Reality Trees
102 2:56 Char Count= 0
N1. Operators
can cope with
the number of
calls Cost of
operation
increases

C1a. Operators Injection: Right-
are experienced size the number
and fast of operators

Injection: Set up a
comprehensive and Not many new
effective training operators
program
Figure 8.11 Identification of new undesirable effects resulting from injections.

8.4.1 Comparison of CRT, RCA, FMEA and C&E matrix
The four current Six Sigma tools are compared in Table 8.4. The objective is to organize
and understand the similarities and differences between them.

8.4.2 CRT and RCA
RCA is the most direct ‘competitor’of the CRT. Both employ the cause--effect thinking
process and produce similar-looking diagrams .The purpose of CRT is to search for
the ‘root causes’ of a list of ‘Negative effects’. The objective of RCA is to trace the
‘root causes’ of a given problem. The differences between them are generally subtle,
but may be significant at times. In the Six Sigma strategy, these are supposed to be in
different phases, the define phase for the CRT and measure phase for RCA.

8.4.3 FRT vs. QFD, FMEA and DOE
Objectively, we need a tool in the improve phase in order, firstly, to identify the solu-
tions to the problem and, secondly, design a solution if necessary. In the traditional
transactional Six Sigma curriculum, the job is taken care of partly by FMEA (identify
needed solution) and partly by DOE (optimize a process). From experience, FMEA is
not very popular unless it is enforced by management as a system. As for DOE, usage
is even lower. Looking at this scenario, the FRT can be a good alternative for iden-
tifying the needed solutions. As for solution development, QFD and some relevant